JP2007257816A - Method for manufacturing magnetic recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing magnetic recording media, by which a magnetic recording medium that has a recording layer formed in a concavo-convex pattern, a sufficiently flat surface, and good recording/reproducing properties can be manufactured. <P>SOLUTION: A first filling material 36 is deposited over a workpiece 10 having the recording layer 32 where recording elements 32A are formed as convex portions of the concavo-convex pattern so as to cover the recording elements 32A and to fill at least a part of a concave portion. A detection material 44 is deposited over the first filling material 36, a second filling material 45 is deposited over the detection material 44, a surface of the workpiece 10 is irradiated with a process gas to remove at least part of a deposited portion above the top surfaces of the recording elements 32A of the first filling material 36, the detection material 44 and the second filling material 45 to flatten the surface. In the flattening step, a component of the detection material 44 removed from and flying off the workpiece 10 is detected to stop the irradiation with the process gas based on a result of detecting the component of the detection material 44. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a magnetic recording medium having a recording layer with a concavo-convex pattern.

  Conventionally, a magnetic recording medium such as a hard disk has been remarkably improved in surface recording density by improving the fineness of magnetic particles constituting the recording layer, changing the material, miniaturizing the head processing, and the like. Although the improvement in surface recording density is expected, the recording limit of the magnetic head, the recording of incorrect information on the track adjacent to the recording target track due to the expansion of the recording magnetic field of the magnetic head, the crosstalk during playback, etc. However, the improvement of the surface recording density by the conventional improvement method has reached the limit.

  On the other hand, as a candidate for a magnetic recording medium that can realize a further improvement in surface recording density, a discrete track medium in which a recording layer is formed in a concavo-convex pattern and a recording element is formed as a convex part of a concavo-convex pattern, or a pattern Media has been proposed. On the other hand, in a magnetic recording medium such as a hard disk, the flatness of the surface is important in order to stabilize the flying height of the head and obtain good recording / reproducing characteristics. Accordingly, it has been proposed to fill the recesses between the recording elements with a filler, and to flatten the upper surfaces of the recording elements and the filler (for example, see Patent Document 1).

  As a method for processing the recording layer into the concavo-convex pattern, a processing method such as dry etching can be used. As a method of filling the concave portion with a filler and flattening the recording element and the upper surface of the filler, a sputtering method, a CVD (Chemical Vapor Deposition) method, an IBD (Ion Beam Deposition) method or the like is applied on the recording layer of the concave-convex pattern. Uses a method to remove the excess filler deposited on the upper side of the recording element (on the opposite side of the substrate) by dry etching after forming the filler and filling the recesses between the recording elements Yes.

  In order to obtain good magnetic properties of the recording layer, it is preferable to completely remove excess filler so as not to process the upper surface of the recording element. That is, it is preferable to control the dry etching in the planarization process so that the processing end point coincides with the upper surface of the recording element.

  In the case of dry etching, secondary ion mass spectrometry (SIMS (Secondary-Ion Mass Spectrometry)) or quadrupole mass spectrometry (QMS (Quadrupole Mass Spectrometry)) is used to remove the components of the recording element that are removed from the workpiece and scatter. By detecting the component of the recording element and stopping the processing, it is possible to suppress the variation of the processing end point within a range of several nm with respect to the upper surface of the recording element.

  However, in order to detect the components of the recording element by secondary ion mass spectrometry or quadrupole mass spectrometry, it is necessary to etch not only the excess filler but also the recording element. Therefore, a portion of about several nanometers near the upper part of the recording element is surely etched, and there is a concern about deterioration of magnetic characteristics.

  On the other hand, in the semiconductor field, a technique is known in which etching is stopped by forming a material to be detected on a portion to be protected from etching corresponding to a recording element and detecting a component of the material to be detected. (For example, refer to Patent Document 2).

  Using this technology also in the field of magnetic recording media, a detection material is deposited on the recording layer of the concavo-convex pattern, etching reaches the detection material, and components of the detection material that are removed and scattered begin to be detected. It is expected to remove the excess filler so that the etching does not reach the recording element by stopping the etching immediately after the detection or immediately after the component of the detected material disappeared.

JP-A-9-97419 JP 2003-078185 A

  However, immediately after the material to be detected begins to scatter, the amount of the component of the material to be detected is small, so that secondary ion mass spectrometry and quadrupole mass spectrometry have detected that the component of the material to be detected has started to be detected. The difference between the data shown and the noise may not be clear, and it may be difficult to detect clearly when the detected material has been etched.

  On the other hand, it is relatively easy to determine that the detected material that has been detected has substantially disappeared, but secondary ion mass spectrometry and quadrupole mass spectrometry are removed and scattered. Therefore, there is a time lag of several seconds between the time when the material to be detected is completely removed from the workpiece and the time when it is determined that the material to be detected has disappeared.

  Therefore, when the etching is stopped immediately after it is determined that the detected material has disappeared, the detected material is actually completely removed from the workpiece, and the etching further proceeds to etch the recording element. is there.

  Further, when the recording elements are etched, the filler filling the recesses between the recording elements is also etched. Since the recording element and the filler are different materials and the processing speed for etching is generally different, the filler filling the recesses together with the recording element is further etched so that the gap between the upper surface of the recording element and the upper surface of the filler A step of about several nanometers may occur. In the case of discrete track media with high surface recording density and patterned media, the flying height of a small head of about 5 to 15 nm is assumed, so even a step of about several nm may cause problems such as head crashes. It can be a cause. Such a step of about several nanometers can occur in the semiconductor manufacturing process as well, but in the case of a semiconductor, there is no problem such as a head crash, so that a step of about several nanometers is generally not a problem.

  The present invention has been made in view of the above problems, and can provide a magnetic recording medium having a recording layer with a concavo-convex pattern, a sufficiently flat surface, and good recording / reproducing characteristics. It aims at providing the manufacturing method of.

  According to the present invention, a first filler is formed on a workpiece having a recording layer on which a recording element is formed as a convex part of a concavo-convex pattern to cover the recording element and at least a concave part between the recording elements is provided. Partially filling, forming a material to be detected on the first filler, forming a second filler on the material to be detected, and irradiating the surface of the workpiece with a processing gas Then, at least a part of the first filler, the material to be detected, and the second filler formed on the upper side of the recording element is removed to flatten the surface. The object is achieved by detecting the component of the material to be detected which is removed from the workpiece and scattered, and stopping the irradiation of the processing gas based on the detection result of the component of the material to be detected.

  Since the first filling material is formed between the recording element and the detected material, the first filling is performed even if etching further proceeds after the detected material on the recording element is completely removed. The material can protect the recording element from etching.

  In addition, when the first filler is formed with a thickness greater than the depth of the concave portion, the etching proceeds further after the detected material on the recording element is completely removed, and the first filler on the recording element. Even if the first filler that fills the recesses between the recording elements together with the filler is etched, the first filler is etched both on the recording elements and on the recesses. No step is produced as in the case of etching.

  When the first filler is deposited to be thinner than the depth of the recess, the upper portion of the recess is filled with the second filler, and etching is performed after the detected material on the recording element is completely removed. As it progresses, the first filler on the recording element and the second filler filling the recesses are etched, but in this case as well, the same material or planarization as the first filler and the second filler By selecting a material having a similar etching rate to the dry etching in the process, it becomes difficult to produce a step as in the case where the recording element and the filler are etched, and the surface can be sufficiently flattened.

  In addition, the dry etching not only removes the convex portion selectively than the concave portion, but also removes the end portion of the convex portion earlier than the central portion. Gradually removed. Therefore, if the width of the recording element is wide, the time difference between the time when the material to be detected above the central part of the recording element is etched and the time when the material to be detected above the edge of the recording element is etched becomes large, and noise is increased. The variation at the time when the amount of scattered material to be detected increases to such an extent that it can be clearly distinguished from the above becomes large. For this reason, it may be difficult to stop the etching at a target position with high accuracy.

  On the other hand, the time difference between the time when the etching is applied to the material to be detected above the central portion of the recess and the time when the etching is applied to the material to be detected above the end of the recess is small, so that the time can be clearly distinguished from noise. The variation at the time when the amount of detection material scattered increases is small. Therefore, after forming the first filler with a thickness equal to or greater than the depth of the recess, the detected material is deposited, and the components of the detected material that are removed from the recess and scattered are detected. If the etching in the planarization process is stopped based on the result, the etching can be stopped at a target position with high accuracy.

  That is, the above-described object can be achieved by the following present invention.

(1) A first filler is formed on a substrate and a workpiece having a recording layer formed on the substrate in a predetermined concavo-convex pattern and having recording elements formed as convex portions of the concavo-convex pattern. A first filler film forming step for covering the recording elements and at least partially filling the recesses between the recording elements; and a detection target for forming a detection material on the first filler A material film forming step, a second filler film forming step for forming a second filler on the material to be detected, and a processing gas on the surface of the workpiece to irradiate a processing gas. A flattening step of flattening the surface by removing at least a part of a portion of the filler, the material to be detected and the second filler formed above the upper surface of the recording element; The components of the detected material that are removed from the workpiece and scattered in the planarization step are executed in order. Out method of manufacturing a magnetic recording medium characterized by stopping the irradiation of the processing gas on the basis of the detection result of the component of 該被 detection material.

(2) In (1), the first filler is deposited with a thickness equal to or greater than the depth of the recess so as to completely fill the recess of the uneven pattern in the first filler deposition step. In the flattening step, irradiation of the processing gas is stopped based on a detection result of a component of the detected material that is removed from the concave portion of the detected material and scattered. Manufacturing method.

(3) In (1) or (2), in the detected material film forming step, the detected material is formed by forming a non-oxide film on the first filler, and the first filling is performed. A method of manufacturing a magnetic recording medium, wherein an oxide is used as at least one of a material and the second filler.

(4) In (3), in the detected material film forming step, the detected material is dispersed on the first filler, and is thin so as not to completely cover the first filler. A method of manufacturing a magnetic recording medium, comprising forming a film.

(5) In any one of (1) to (4), in the planarization step, a component of the detected material is detected by either secondary ion mass spectrometry or quadrupole mass spectrometry. A method for manufacturing a magnetic recording medium.

  In this application, “a recording layer formed with a predetermined concavo-convex pattern and having a recording element formed as a convex portion of the concavo-convex pattern” means that the continuous recording layer is divided into a large number of recording elements with a predetermined pattern. In addition to the recording layer, for example, a recording layer in which the recording elements in the form of tracks are continuous at the end or a recording layer in which the recording elements are partly formed on the substrate, such as a recording layer in which the recording element has a spiral shape, a recess Is formed in the middle of the thickness direction and the substrate side surface is continuous, the continuous recording layer formed following the surface of the concave / convex pattern substrate or the lower layer, the upper surface of the concave / convex pattern substrate or the lower convex portion, and The term “recording layer” is used to include a recording layer formed by being divided on the bottom surface of the recess.

  In this application, the term “the upper surface of the recording element” is used to mean the surface of the recording layer opposite to the substrate.

  In addition, the term “magnetic recording medium” in the present application is not limited to a hard disk, a floppy (registered trademark) disk, a magnetic tape, or the like that uses only magnetism for recording and reading information, and MO (Magneto) using both magnetism and light. It is used in the meaning including a magneto-optical recording medium such as Optical) and a heat-assisted recording medium using both magnetism and heat.

  According to the present invention, a magnetic recording medium having a recording layer with a concavo-convex pattern, a sufficiently flat surface, and good recording / reproducing characteristics can be manufactured.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

  In the first embodiment of the present invention, the continuous recording layer 20 is formed by processing the starting body of the workpiece 10 formed by forming the continuous recording layer 20 and the like on the substrate 12 as shown in FIG. As shown in FIG. 2, the recording layer 32 having a predetermined concavo-convex pattern is formed by dividing into a large number of recording elements 32A, and a first filler 36 or the like is formed on the recording layer 32 to form the recording elements 32A. The present invention relates to a method of manufacturing the magnetic recording medium 30 by filling the recesses 34 between them and removing the excess first filler 36 and the like above the upper surface of the recording element 32A to flatten the surface. It has a feature in the process of removing the first filler 36 and the like to flatten the surface. The other steps are not considered particularly important for the understanding of the first embodiment, and thus the description thereof will be omitted as appropriate.

  The starting body of the workpiece 10 shown in FIG. 1 includes a base layer 14, an antiferromagnetic layer 15, a soft magnetic layer 16, an orientation layer 18, a continuous recording layer 20, and a first mask layer 22 on a substrate 12. The second mask layer 24 and the resist layer 26 are formed in this order.

The material of the substrate 12 is glass, Al ₂ O ₃ or the like. The underlayer 14 has a thickness of 2 to 40 nm and is made of Ta or the like. The antiferromagnetic layer 15 has a thickness of 5 to 50 nm and is made of a PtMn alloy, a RuMn alloy, or the like. The soft magnetic layer 16 has a thickness of 50 to 300 nm and is made of an Fe alloy or a Co alloy. The alignment layer 18 has a thickness of 2 to 40 nm, and is made of a nonmagnetic CoCr alloy, Ti, Ru, a laminate of Ru and Ta, MgO, or the like.

  The continuous recording layer 20 has a thickness of 5 to 30 nm and is made of a CoCr alloy. The first mask layer 22 has a thickness of 3 to 50 nm and is made of C (carbon). The second mask layer 24 has a thickness of 1 to 30 nm and is made of Ni. The resist layer 26 has a thickness of 30 to 300 nm and is made of resin.

  The magnetic recording medium 30 is a perpendicular recording type discrete track medium.

  A large number of recording elements 32A of the recording layer 32 are formed in the data region in the shape of concentric arc-shaped tracks at fine intervals in the radial direction. The recording element 32A is formed with a predetermined servo pattern including a contact hole in the servo area.

As the first filler 36, a nonmagnetic oxide such as SiO ₂ can be used.

  On the recording element 32A and the first filler 36, a protective layer 38 and a lubricating layer 40 are formed in this order. The material of the protective layer 38 is a hard carbon film called diamond-like carbon. The material of the lubricating layer 40 is PFPE (perfluoropolyether).

  Next, a method for manufacturing the magnetic recording medium 30 will be described along the flowchart shown in FIG.

  First, a workpiece manufacturing process is executed (S102). Specifically, the starting body of the workpiece 10 shown in FIG. 1 is processed, and the recording element 32A is formed as a convex / concave pattern on the substrate 12 as shown in FIG. A workpiece 10 having the formed recording layer 32 is produced.

  The starting body of the workpiece 10 is a substrate 12, an underlayer 14, an antiferromagnetic layer 15, a soft magnetic layer 16, an orientation layer 18, a continuous recording layer 20, a first mask layer 22, and a second mask layer. 24 is formed by sputtering in this order, and further a resist layer 26 is applied by spin coating.

Using a transfer device (not shown), a concavo-convex pattern corresponding to the concavo-convex pattern of the recording layer 32 is transferred to the resist layer 26 as a starting body of the workpiece 10 by a nano-imprint method as shown in FIG. The resist layer 26 at the bottom of the recess is removed by reactive ion beam etching using O ₂ or O ₃ gas as a reactive gas. The resist layer 26 may be exposed and developed to process the resist layer 26 into a concavo-convex pattern.

Next, the second mask layer 24 at the bottom of the recess is removed by ion beam etching using Ar gas. Further, the first mask layer 22 at the bottom of the recess is removed by reactive ion etching using SF ₆ gas. Next, the continuous recording layer 20 at the bottom of the recess is removed by ion beam etching using Ar gas, and the continuous recording layer 20 is divided into a large number of recording elements 32A. Note that the first mask layer remaining on the recording element 32A is removed by reactive ion etching using SF ₆ gas.

  As a result, as shown in FIG. 5, the substrate 10 and the workpiece 10 having the recording layer 32 formed on the substrate 12 in a concavo-convex pattern and having the recording elements 32A formed as the convex portions of the concavo-convex pattern are obtained. It is done.

  Next, a first filler film forming step is executed (S104). Specifically, as shown in FIG. 6 by bias sputtering, the first filler 36 is formed on the recording layer 32 so as to cover the recording element 32A and completely fill the concave portion 34. The film is formed with a thickness greater than that (thickness in the recess 34). The thickness of the first filler 36 is preferably 0 to 10 nm thicker than the depth of the recess 34. Since the particles of the first filler 36 try to be uniformly deposited on the surface of the workpiece 10, the surface has an uneven shape. By applying a bias voltage to the workpiece 10, the sputtering gas is It is urged in the direction of the workpiece 10 and collides with the deposited first filler 36, and a part of the deposited first filler 36 is etched. This etching action tends to selectively remove the protruding portion of the deposited first filler 36 from its end portion earlier than the other portion (the surrounding non-protruding portion). The convex portion on the surface above 32A has a smaller width than the recording element 32A. When the film forming action exceeds the etching action, film formation proceeds while suppressing surface irregularities. As a result, the first filler 36 is formed in a shape in which unevenness on the surface is suppressed to some extent so as to cover the recording element 32A.

  Next, a detected material film forming step is executed (S106). Specifically, as shown in FIG. 7, the detection target material 44 is formed on the first filler 36 by sputtering. The detected material 44 can be formed by depositing a non-oxide such as Nb containing an element different from the elements constituting the recording layer 32, the first filler 36, and the second filler 45. The material to be detected 44 is uniformly formed following the irregularities on the surface of the first filler 36. In the first embodiment, the detected material 44 is formed so as to completely cover the first filler 36. The thickness of the material to be detected 44 is preferably 5 nm or less in consideration of manufacturing efficiency and the like.

  When the non-oxide such as Nb comes into contact with the first filler 36 that is an oxide, the lower surface portion is oxidized by the diffusion of oxygen in the first filler 36.

Next, a second filler film forming step is executed (S108). Specifically, the second filler 45 is deposited on the detected material 44 as shown in FIG. 8 by bias sputtering as in the first filler deposition step (S104). As the second filler 45, similarly to the first filler 36, a nonmagnetic oxide such as SiO ₂ can be used. When the second filler 45, which is an oxide, is formed in contact with the upper surface of the detected material 44, oxygen in the second filler 45 diffuses on the upper surface of the detected material 44, and the detected material is detected. The upper surface portion of the material 44 is oxidized. In other words, as shown in the enlarged view of FIG. 9, the detected material 44 is oxidized in the vicinity of the upper surface 44A and the lower surface 44B.

  Next, a planarization process is performed (S110). Specifically, as shown by arrows in FIG. 10, ion beam etching irradiates a processing gas such as Ar gas from a direction inclined with respect to the normal line of the surface of the workpiece 10 to obtain the first The portion formed on the upper side (opposite side of the substrate 12) of the recording element 32A of the filler 36, the detected material 44, and the second filler 45 is removed. Thus, by irradiating the processing gas from a direction inclined with respect to the normal line of the surface of the workpiece 10, the tendency to remove the convex portion faster than the concave portion is increased.

  At this time, ion beam etching is controlled while detecting components of the material 44 to be detected that are removed from the workpiece 10 and scattered by secondary ion mass spectrometry, quadrupole mass spectrometry, or the like.

  Immediately after the material to be detected 44 starts to scatter, the amount of scattering of the component of the material to be detected 44 is small, and the difference between the data indicating the detection of the component of the material to be detected 44 and noise may not be clear.

  In addition, dry etching such as ion beam etching not only removes the convex portion selectively rather than the concave portion, but also removes the end portion of the convex portion earlier than the central portion, thereby detecting the detection on the recording element 32A. The material 44 is gradually removed from the ends. When the width of the recording element 32A is wide, there is a large time difference between the time when the detected material 44 on the center of the recording element 32A is etched and the time when the detected material 44 on the end of the recording element 32A is etched. Therefore, the variation at the time when the amount of scattering of the detected material 44 increases to such an extent that it can be clearly distinguished from noise also increases. Therefore, when the width of the recording element 32A is wide, if the irradiation of the processing gas is stopped based on the detection of the component of the detected material 44 that is removed from the recording element 32A and scattered, the etching is performed. It is difficult to stop with high accuracy at the position.

  On the other hand, when the etching further proceeds and the detected material 44 on the concave portion 34 is exposed as shown in FIG. 11, most of the detected material 44 on the concave portion 34 is irrespective of the width of the concave portion 34. Since the variation at the time when the amount of scattering of the detected material 44 increases to such an extent that it can be clearly distinguished from noise is detected at the same time, the component of the detected material 44 that is removed from the concave portion 34 and scattered is detected. If the processing gas irradiation is stopped based on this, etching can be stopped at a target position with high accuracy.

  As shown in FIG. 12, the scattering amount of the detected material 44 gradually increases after the start of etching, but once decreases when the detected material 44 on the recording element 32A is removed. When the etching reaches the detected material 44 on the concave portion 34, the amount of scattering of the detected material 44 increases again, and rapidly decreases when the detected material 44 on the concave portion 34 is removed. Therefore, it can be detected that etching has reached the detected material 44 on the recess 34 based on the increase or decrease in the amount of scattering of the detected material 44 in the latter half.

  In the first embodiment, the irradiation of the processing gas is stopped based on the detection result of the component of the detected material 44 that is removed from the concave portion 34 of the detected material 44 and scattered, and the etching is stopped. For example, it is determined that the detected material 44 on the concave portion 34 is etched and the detected amount of the component of the detected material 44 reaches the maximum value, and further, the etching progresses and the detected material 44 is substantially lost. At that time, irradiation of the processing gas is stopped, and etching is stopped.

  Further, based on a predetermined reference value of the detected amount of the component of the detected material 44, the irradiation of the processing gas may be stopped when the detected amount reaches the reference value, and for a certain time from that point. You may make it stop irradiation of the processing gas later.

  In addition, in the secondary ion mass spectrometry and the quadrupole mass spectrometry, the detected material is more easily etched when the oxide is etched than when the single element constituting the detected material is etched. The detection amount of the constituent elements increases. In the first embodiment, since the second filler 45 is an oxide and the portion in the vicinity of the upper surface 44A of the detected material 44 is oxidized, it is easy to detect when the detected material 44 starts to scatter. It has become. Further, since the first filler 45 is also an oxide, and the portion near the lower surface 44B of the detected material 44 is oxidized, it is easy to detect when the detected material 44 disappears.

  As described above, in order to oxidize only portions of the detected material 44 near the upper surface 44A and the lower surface 44B, the detected material 44 is preferably 3 nm or more. When only the portions in the vicinity of the upper surface 44A and the lower surface 44B of the detected material 44 are oxidized, the amount of scattering of the detected material 44 depends on whether the detected material 44 on the recording element 32A is etched or in the recess 34. While the upper detection material 44 is etched, it increases and decreases twice, and as a whole, the scattering amount of the detection material 44 may increase and decrease three to four times. It is possible to identify the increase / decrease in the amount of scattering of the detected material 44 when the detected material 44 is etched and the increase / decrease in the amount of scattering of the detected material 44 when the detected material 44 on the recess 34 is etched. It is easy to detect that the material to be detected 44 on the recess 34 has been etched.

  On the other hand, if the detected material 44 is formed to be thinner than 1 nm, for example, the detected amount of the component of the detected material 44 is maximized (maximum) only once in the latter half of the etching of the detected material 44 on the recess 34. Therefore, it is easy to determine when the amount of scattering of the detection target material 44 reaches the maximum value.

  Since secondary ion mass spectrometry and quadrupole mass spectrometry detect substances that are removed and scattered, there is a time lag between when the substance is actually removed and when the substance is detected. There is. Therefore, even if the etching is stopped based on the detection result of the component of the detected material 44, the etching may actually further proceed after the detected material 44 is completely removed.

  However, the first filler 36 is formed to be thicker than the depth of the recess 34, and the lower surface of the detected material 44 is located 0 to 10 nm above the upper surface of the recording element 32A (on the side opposite to the substrate 12). Therefore, even if the etching is stopped after the detected material 44 is completely removed, the recording element 32A is protected from the etching. Even if the etching reaches the upper surface of the recording element 32A, the processing amount of the recording element 32A is suppressed to a minute amount so that the influence on the magnetic characteristics can be ignored.

  Even if the etching progresses further after the material to be detected 44 is completely removed and the first filler 36 filling the recess 34 together with the first filler 36 on the recording element 32 is etched, the recess Since the first filler 36 is etched both on the recording element 32A and on the recording element 32A, a step difference is hardly generated as in the case where the recording element and the filler are etched, and the surface can be sufficiently flattened.

  The first filler 36 is equal to the thickness of the first filler 36 under the detected material 44 to be etched after the detected material 44 is completely removed until the etching stops. By forming a film thicker than the depth of the concave portion 34, it is possible to prevent the etching of the upper surface of the recording element 32A or to sufficiently suppress the influence on the magnetic characteristics.

  Next, a protective layer 38 is formed with a thickness of 1 to 5 nm on the upper surface of the recording element 32A and the first filler 36 by the CVD method (S112), and further, 1 to 3 is formed on the protective layer 38 by the dipping method. The lubricating layer 40 is formed with a thickness of 2 nm (S114). Thereby, the magnetic recording medium 30 shown in FIG. 2 is completed.

  Next, a second embodiment of the present invention will be described.

  In the first embodiment, the detected material 44 is formed so as to completely cover the first filler 36 in the detected material film forming step (S106), whereas in the second embodiment, It is characterized in that the material to be detected 44 is dispersed on the first filler 36 and is thinly formed so as not to completely cover the first filler 36. Since other steps are the same as those in the first embodiment, the same reference numerals as those in the first embodiment are used, and the description thereof is omitted as appropriate.

  In this way, when the material to be detected 44 is dispersed on the first filler 36 and thinly formed so as not to completely cover the first filler 36, as shown in FIG. The detection material 44 does not become a continuous film, and most of the detection material 44 is oxidized by the diffusion of oxygen from the first filler 36 or the second filler 45, so that the detection amount of the detection material 44 is small. growing.

  In addition, by thinly forming the first filler 36 as described above, the detected amount of the component of the detected material 44 is maximized only once in the latter half of the etching of the detected material 44 on the recess 34 (maximum). Therefore, it is easy to determine when the detected amount reaches the maximum value. Furthermore, since the detection amount becomes maximum (maximum) only once, the detection amount also increases at this point.

  That is, the detection amount of the material to be detected 44 by the secondary ion mass spectrometry and the quadrupole mass spectrometry becomes large, and even if the material to be detected 44 is formed to be thinner than 1 nm, the etching is performed up to the material to be detected 44. It is possible to clearly detect what has been reached. In order to increase the detection amount of the material to be detected 44, it is preferable to form the material to be detected 44 with a thickness of 0.3 to 1 nm, and preferably with a thickness of 0.4 to 0.6 nm. More preferred. Note that it is difficult to actually measure the thickness of the material to be detected 44 thus thinly formed, and the thickness of the material to be detected 44 is a thickness calculated from the film formation rate and the film formation time. This shows the target value.

  Next, a third embodiment of the present invention will be described.

  In the first embodiment, in the first filler film forming step (S104), the first filler 36 is formed on the recording layer 32 with a thickness greater than the depth of the recess 34 so that the recess 34 is completely filled. While the film was deposited and the irradiation of the processing gas was stopped based on the detection result of the component of the detected material 44 on the concave portion 34, the third embodiment records as shown in FIG. The first filler 36 is deposited on the layer 32 to be thinner than the depth of the recess 34, and the irradiation of the processing gas is stopped based on the detection result of the component of the detected material 44 on the recording element 32A. It is characterized by. The recess 34 is filled with the first filler 36, the material to be detected 44 and the second filler 45. Since other steps are the same as those in the first embodiment, the same reference numerals as those in the first embodiment are used, and the description thereof is omitted as appropriate.

  In the third embodiment, as shown in FIG. 15, in the planarization step (S110), when the detection material 44 on the recording element 32A is etched, it is removed and scattered. The component is detected and the etching is stopped. That is, the etching is stopped by detecting that the etching has reached the material 44 to be detected on the recording element 32A.

  Also in the third embodiment, since the first filler 36 is formed between the recording element 32A and the detected material 44, the detected material 44 on the recording element 32A is completely removed. Even if the etching further proceeds, the recording element 32A can be protected from the etching by the first filler 36.

Also in the third embodiment, after the detected material 44 on the recording element 32A is completely removed, the etching further proceeds to fill the first filler 36 and the recess 34 on the recording element 32A. Even if the second filler 45 is etched, SiO ₂ (the first filler 36 and the second filler 45) is etched both on the recording element 32A and on the recess 34. A level difference is unlikely to occur when the filler is etched, and the surface can be sufficiently flattened.

  Also in the third embodiment, portions near the upper surface 44A and the lower surface 44B of the non-oxide detected material 44 are oxidized by the diffusion of oxygen from the first filler 36 and the second filler 45. Therefore, the detection amount of the material to be detected 44 by the secondary ion mass spectrometry and the quadrupole mass spectrometry is increased, and it can be detected that the etching has reached the material 44 to be detected.

  Also in the third embodiment, as in the second embodiment, the detection material 44 is dispersed on the first filler 36 in the first filler film forming step (S104), and the first filler The filler 36 may be thinly formed so as not to be completely covered.

  In the first to third embodiments, Nb is exemplified as the material to be detected 44. However, as the material to be detected, for example, Al, Y, Zr, Rh, Ag, Tb, Ta, Au, Bi, Ti, Other elements such as In and W may be used. The detected material 44 may be a material composed of a single element different from the elements constituting the recording layer 32, or may be a material composed of a plurality of elements selected from these elements and Nb. Good. Further, for example, these elements or oxides of Nb may be used as the material to be detected. Thus, by using an oxide as a material to be detected, an effect of increasing the detection amount by secondary ion mass spectrometry and quadrupole mass spectrometry can be obtained. Metal elements with a large atomic number, such as Nb, which are relatively easy to detect by secondary ion mass spectrometry and quadrupole mass spectrometry, are easier to form when they are not oxidized than oxides. Therefore, as in the first to third embodiments, an oxide is used as at least one of the first filler and the second filler, and oxygen from the first filler and the second filler is reduced. It is preferable to oxidize the material to be detected by diffusion. Even when a part or all of the detected material 44 is an oxide, the detected material 44 scattered is detected based on the mass number of a single element. For Zr, Ag, Ta, Ti, In, and W, it is preferable to detect the material to be detected 44 scattered based on the mass number of the isotope having the highest abundance ratio in the natural world among a plurality of isotopes.

In the first to third embodiments, the first filler 36 and the second filler 45 are both SiO ₂ , but different oxidation is used as the first filler 36 and the second filler 45. You may use things. Further, a non-oxide may be used as one of the first filler 36 and the second filler 45. Further, both the first filler 36 and the second filler 45 may be non-oxides. In the case where the second filler fills the upper portion of the recess 34 as in the third embodiment, the first filler 36 and the second filler 45 have an etching rate for dry etching in the planarization step (S110). Is preferably a close material.

  In the third embodiment, the second filler 45 fills the recess 34, whereas in the first and second embodiments, the first filler 36 is greater than the depth of the recess 34. The second filler 45 does not fill the concave portion 34, but in this case, the term “second filler” is used in this application for convenience.

In the first to third embodiments, ion beam etching using Ar gas is exemplified as dry etching in the planarization step (S110). However, other rare gases such as Kr and Xe are used. Ion beam etching may be employed, and for example, reactive ion etching using a halogen-based reaction gas such as SF ₆ , CF ₄ , C ₂ F _6, or a mixed gas of a reaction gas and a rare gas is used. Other dry etching such as reactive ion beam etching may be employed.

  In the first to third embodiments, as a method of detecting the component of the detection target material 44 that is removed from the workpiece 10 and scattered in the planarization step (S110), secondary ion mass spectrometry or fourth method is used. Although the quadrupole mass spectrometry is exemplified, other methods may be used as long as the components of the detected material 44 that are removed from the workpiece 10 and scattered can be detected with high accuracy.

  In the first to third embodiments, the first filler 36 and the second filler 45 are formed by the bias sputtering method. For example, the sputtering method or the CVD method in which no bias power is applied. The first filler 36 and the second filler 45 may be deposited using other deposition methods such as the IBD method.

  In the first to third embodiments, the surface of the workpiece 10 is flattened only by the flattening step (S110), but after the flattening step (S110), for example, another layer is formed, Further, planarization by dry etching or the like may be performed.

  In the first to third embodiments, the material of the continuous recording layer 20 (recording element 32A) is a CoCr alloy. For example, other alloys containing iron group elements (Co, Fe, Ni), these alloys Other materials such as a laminate may be used.

  In the first to third embodiments, the underlayer 14, the antiferromagnetic layer 15, the soft magnetic layer 16, and the orientation layer 18 are formed under the continuous recording layer 20. The layer configuration may be changed as appropriate according to the type of the magnetic recording medium. For example, one or more of the underlayer 14, the antiferromagnetic layer 15, the soft magnetic layer 16, and the orientation layer 18 may be omitted. Further, the continuous recording layer may be directly formed on the substrate.

  In the first to third embodiments, the magnetic recording medium 30 has the recording layer 32 or the like formed only on one side of the substrate 12. However, the magnetic recording medium 30 is a double-sided recording type magnetic recording medium having recording layers on both sides of the substrate. The present invention can also be applied to manufacturing.

  In the first to third embodiments, the magnetic recording medium 30 is a perpendicular recording type discrete track medium in which the recording layer 32 is divided at fine intervals in the track radial direction. PERM (Pre) having a magnetic disk divided in a fine interval in the direction (sector direction), patterned media divided in a fine interval in both the radial direction and the circumferential direction of the track, and a continuous recording layer of concavo-convex patterns The present invention is naturally applicable to the manufacture of a magnetic disk of the −Embossed Recording Medium) type and a magnetic disk in which the recording layer has a spiral shape. The present invention is also applicable to the manufacture of a magnetic recording medium having an in-plane recording type recording layer. The present invention is also applicable to the manufacture of magneto-optical disks such as MO, heat-assisted magnetic disks using both magnetism and heat, and magnetic recording media having a recording layer with a concavo-convex pattern other than the disk shape, such as magnetic tape. Is applicable.

  Nine types of samples A to J were produced 10 by 10 as in the first and second embodiments. Specifically, 90 workpieces 10 each having a substrate 12 having a diameter of 48 mm and a recording layer 32 having the following uneven pattern were prepared.

Track pitch: 150 nm
Width of convex part: 90 nm
Recess width: 60 nm
Concavity and convexity step (depth of recess 34): 18 nm
Range in which the concave / convex pattern is formed: a range of 16 to 18 mm in radius from the center

Next, the first filler 36 was deposited on the recording layer 32 of the workpiece 10 to be thicker than the depth of the recess 34 by bias sputtering to completely fill the recess 34. The conditions for bias sputtering are as follows. Incidentally, the first sealing member 36 with SiO _2.

Deposition power (power applied to SiO ₂ target): RF 500 W
Bias power applied to workpiece 10: RF 150W
Chamber pressure: 0.3 Pa
Distance between target and workpiece: 250 nm
Film thickness (thickness of the first filler 36 on the recess 34): 20 nm

  Next, a film of Nb was formed on the first filler 36 as the material to be detected 44 by sputtering. The film thickness of the detected material 44 was different for each of A to J. Table 1 shows the thickness of the detected material 44 for each of A to J. The film thicknesses of these materials to be detected 44 are values calculated from the film formation rate and the film formation time.

Next, a second filler 45 was formed on the material to be detected 44 of the workpiece 10 by bias sputtering. SiO ₂ was used as the second filler 45. The conditions for bias sputtering are as follows.

Deposition power (power applied to SiO ₂ target): RF 500 W
Bias power applied to workpiece 10: RF 150W
Chamber pressure: 0.3 Pa
Distance between target and workpiece: 250 nm
Film thickness (thickness of second filler 45 on recess 34): 40 nm

  Next, the surplus first filler 36, detected material 44 and second filler 45 above the upper surface of the recording element 32A were removed by ion beam etching, and the surface was flattened. The ion beam etching conditions are as follows. The incident angle of the ion beam is an angle with respect to the surface of the workpiece 10.

Ion beam incident angle: approx. 2 °
Beam voltage: 700V
Beam current: 1100 mA
Suppressor voltage: 400V
Ar gas flow rate: 11 sccm
Chamber pressure: 0.04 Pa

  At this time, the secondary ion mass spectrometry detects Nb (component of the material to be detected 44) that is removed from the workpiece 10 and scatters, and ion beam etching is performed when the Nb count number substantially disappears. Stopped. Here, the Nb count number is a value corresponding to the scattering amount of Nb. Note that the background value of the Nb count number may show a value of about 2000 (count / sec) due to noise even while only the outermost second filler 45 is being etched. After the Nb count number reaches a maximum (in the latter half of the etching of the detection material 44 on the substrate), the time when the detection material 44 has substantially disappeared is defined as the time when the detection material 44 has substantially disappeared. Ion beam etching was stopped. Since there are two maximum values for H and J, the time when the detected material 44 substantially disappeared was the time when the value decreased to half of the subsequent maximum value.

  Table 1 shows the time required for flattening A to J and the maximum value of the Nb count immediately before the Nb count disappears substantially. FIG. 16 shows the relationship between the count number of Nb detected in the flattening of A to C and F to H among A to J and time. In addition, the codes A to C and F to H in FIG. 16 indicate that the curves with these are the data of A to C and F to H, respectively. In FIG. 16, the zero point on the horizontal axis is not the time when the flattening process by ion beam etching is started, but the time slightly before the time when the detected material 44 on the recess starts to be detected. . That is, FIG. 16 is a graph after the detected material 44 on the recording element 32A is removed.

  After flattening, the step between the upper surface of the recording element 32A of each sample A to J and the upper surface of the first filler 36 filling the recess 34 was measured by AFM (Atomic Force Microscope). The measurement results are shown in Table 1. In addition, the level | step difference shown in Table 1 is an arithmetic mean value of the level | step difference of 10 samples in AJ. Table 2 shows the standard deviation of the level difference of each sample and the level difference of 10 samples for each of A to J. The level difference of each sample shown in Table 2 is an arithmetic average value of the level difference between the upper surface of the recording element 32A and the upper surface of the first filler 36 filling the concave portion 34 in a plurality of portions of each sample. In Tables 1 and 2, the case where the upper surface of the recording element is higher than the upper surface of the first filler 36 is shown as plus, and the case where it is lower is shown as minus.

  Ten types (K) of 10 samples were produced as in the third embodiment. The concave / convex pattern of the recording layer 32 of the workpiece 10 is the same as A to J in the first embodiment. In addition, since there are many manufacturing conditions that are common to A to J of the first embodiment, description of common items is omitted.

  Ten workpieces 10 having a recording layer 32 with a concavo-convex pattern were prepared, and a first filler 36 was formed on the recording layer 32 of the workpiece 10 to be thinner than the depth of the recesses 34. Specifically, the first filler 36 was formed with a thickness of 2 nm (the thickness of the first filler 36 on the recess 34).

  Next, the material to be detected 44 was formed to a thickness of 0.5 nm on the first filler 36 by sputtering.

  Next, the second filling material 45 was formed in a thickness of 58 nm on the material to be detected 44 of the workpiece 10 by bias sputtering to completely fill the recess 34.

  Next, the surplus first filler 36, detected material 44 and second filler 45 above the upper surface of the recording element 32A were removed by ion beam etching, and the surface was flattened.

  At this time, Nb (component of the material to be detected 44) that was removed from the workpiece 10 and scattered was detected by secondary ion mass spectrometry in the same manner as in Example 1, and the count number of Nb substantially disappeared. At that time, ion beam etching was stopped.

  After planarization, the step between the upper surface of the recording element 32A of each sample of K and the upper surface of the second filler 45 filling the concave portion 34 was measured by AFM. The measurement results and the like are shown in Table 1 and Table 2 as in Example 1.

  One type (L) of ten samples, in which the concave / convex pattern of the recording layer 32 is different from E in Example 1, was prepared. Specifically, a sample having a recording layer 32 having the following concavo-convex pattern in which the width of the recording element 32A is wider than E of Example 1 was prepared.

Track pitch: 300nm
Width of convex part: 180 nm
Recess width: 120 nm
Concavity and convexity step (depth of recess 34): 18 nm
Range where uneven pattern is formed: Range of radius 16-18mm from the center

  The other conditions are the same as E in Example 1 above.

  After flattening, the step between the upper surface of the recording element 32A of each sample of L and the upper surface of the first filler 36 filling the recess 34 was measured by AFM. The measurement results and the like are shown in Table 1 and Table 2 as in Example 1.

  With respect to K in Example 2, ten samples of one type (M) in which the uneven pattern of the recording layer 32 is the same as L in Example 3 and the width of the recording element 32A is wider than K were prepared. . Other conditions are the same as K in the second embodiment.

  After planarization, the step between the upper surface of the recording element 32A of each sample of M and the upper surface of the second filler 45 filling the concave portion 34 was measured by AFM. The measurement results and the like are shown in Table 1 and Table 2 as in Example 1.

[Comparative example]
With respect to K in Example 2 described above, the first material 36 is not formed, and the detected material 44 is directly formed on the recording layer 32 with a thickness of 0.5 nm. A second filler 45 was directly formed thereon with a thickness of 60 nm. The other conditions were the same as in Example 2 above, and 10 samples of one type (X) were produced.

  After planarization, the step between the upper surface of the recording element 32A of each sample of X and the upper surface of the second filler 45 filling the concave portion 34 was measured in the same manner as in Example 1 by AFM. The measurement results and the like are shown in Table 1 and Table 2 as in Example 1.

  As shown in Table 1, X of the comparative example had a large surface level difference of 1.9 nm. This is presumably because the etching further progressed after the material to be detected 44 was completely removed, and the upper surface of the recording element 32A and the upper surface of the second filler 45 filling the recess 34 were etched. Therefore, there is a concern about the deterioration of magnetic characteristics due to the etching of the recording element 32A.

  On the other hand, the samples A to M of Examples 1 to 4 all had a surface level difference of ± 0.3 nm. This is presumably because the etching was stopped with high accuracy near the position of the upper surface of the recording element 32. That is, according to the first to fourth embodiments, the recording element 32A and the first filler 36 (or the second filling) are prevented while preventing the processing of the upper surface of the recording element 32A or suppressing the influence on the magnetic characteristics to be negligible. It was confirmed that the upper surface of the material 45) can be sufficiently flattened.

  Further, among samples A to J of Example 1, samples C to G in which the film thickness of the detected material 44 is 0.3 to 1 nm have a large maximum value (maximum value) of the Nb count number. In Samples D to F in which the film thickness of the detection material 44 is 0.4 to 0.6 nm, the maximum value (maximum value) of the Nb count number was particularly large. This is because the material to be detected 44 is dispersed on the first filler 36 and thinly formed so as not to cover the first filler 36, and the first filler 36 and the second filler 36 are formed. This is probably because most of the detected material 44 was oxidized by the diffusion of oxygen from the material 45.

  In Samples A and B where the film thickness of the material to be detected 44 is less than 0.3 nm, the maximum value (maximum value) of the Nb count number was relatively small. This is considered because the detected material 44 is too thin and the absolute amount of the detected material 44 scattered is too small. In order to increase the detection amount of the material to be detected 44, the film thickness of the material to be detected 44 is preferably 0.3 to 1 nm, more preferably 0.4 to 0.6 nm. I understand.

  Further, as shown in FIG. 16, in the sample H in which the film thickness of the detected material 44 is 3 nm, the count number of Nb detected in the planarization (the detected material 44 on the recess 34 is etched). In the second half) had two local maxima. This is probably because the material to be detected 44 is thick and only the portions near the lower surface of the upper surface 44A and the lower surface 44B are oxidized.

  Moreover, M of Example 4 had a larger standard deviation of the level difference of 10 samples than A to L of Examples 1 to 3. That is, the variation in the level difference of the 10 samples was large. This is because M of Example 4 is produced by stopping the flattening etching based on the detection of the detection target material 44 on the convex portion as in the third embodiment, and further according to Examples 1 and 2. This is probably because the width of the convex portion is wider than A to K, and the variation at the time when the amount of scattering of the detected material 44 increases to such a degree that it can be clearly distinguished from noise.

  On the other hand, the width of the convex part of the concavo-convex pattern is 180 nm, which is the same as M in Example 4, and the standard deviation of the level difference of 10 samples is equivalent to AK in Examples 1 and 2 Met. Since Example 3 was produced by stopping the planarization etching based on the detection of the detected material 44 on the recess as in the first and second embodiments, it can be clearly distinguished from noise. It is considered that the variation at the time when the amount of scattering of the detected material 44 increased was small.

  That is, even when the width of the convex portion is wide, the first filler is thicker than the depth of the concave portion so as to completely fill the concave portion of the concave-convex pattern as in the first and second embodiments. In the flattening process, the surface of the detected material is removed from the top of the recesses, and the processing gas irradiation is stopped based on the detection result of the detected material component. It was confirmed that it can be suppressed to a small size.

  The present invention can be used, for example, to manufacture a magnetic recording medium having a concavo-convex pattern recording layer such as a discrete track medium or a patterned medium.

Side sectional view which shows typically the structure of the starting body of the to-be-processed body which concerns on 1st Embodiment of this invention. Side sectional view schematically showing the structure of a magnetic recording medium obtained by processing the workpiece Flow chart showing an outline of the manufacturing process of the magnetic recording medium Side sectional view which shows typically the uneven | corrugated pattern transcribe | transferred to the resist layer of the starting body of the said to-be-processed body Side sectional view schematically showing the shape of the workpiece with the continuous recording layer divided Side sectional view which shows typically the said to-be-processed object in which the 1st filler was formed into a film Side sectional view schematically showing the workpiece on which the material to be detected is formed Side sectional view which shows typically the said to-be-processed object in which the 2nd filler was formed into a film Side sectional view schematically showing an enlarged structure of the material to be detected Side sectional view schematically showing the object to be processed in which etching reaches a detection material on a recording element in a flattening step. Side cross-sectional view schematically showing the object to be processed in which etching has reached the material to be detected on the recess in the flattening step A graph schematically showing the relationship between the amount of material to be detected and the time in the flattening process Side sectional view which shows typically the structure of the periphery of the to-be-detected material of the to-be-processed body which concerns on 2nd Embodiment of this invention. Side sectional view which shows typically the to-be-processed object in which the 1st filler, to-be-detected material, and 2nd filler which concern on 3rd Embodiment of this invention were formed into a film Side cross-sectional view schematically showing the same workpiece in which etching has reached the detected material on the recording element in the flattening step The graph which shows the relationship between the count number of Nb detected in the planarization of the Example of this invention, and time.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Work object 12 ... Substrate 14 ... Underlayer 15 ... Antiferromagnetic layer 16 ... Soft magnetic layer 18 ... Orientation layer 20 ... Continuous recording layer 22 ... 1st mask layer 24 ... 2nd mask layer 26 ... Resist layer DESCRIPTION OF SYMBOLS 30 ... Magnetic recording medium 32 ... Recording layer 32A ... Recording element 34 ... Recessed part 36 ... 1st filler 38 ... Protective layer 40 ... Lubricating layer 44 ... Detection material 44A ... Upper surface 44B ... Lower surface 45 ... 2nd filler S102 ... Workpiece manufacturing process S104 ... first filler film forming process S106 ... detected material film forming process S108 ... second filler film forming process S110 ... flattening process S112 ... protective layer film forming process S114 ... lubricating layer forming Membrane process

Claims (5)

  The recording material is formed by forming a first filler on a substrate and a workpiece having a recording layer formed on the substrate in a predetermined concavo-convex pattern and having recording elements formed as convex portions of the concavo-convex pattern. A first filler film forming step for covering the elements and at least partially filling the recesses between the recording elements; and a film formation for the detection material for forming the detection material on the first filler A step, a second filler film forming step of forming a second filler film on the detected material, and a surface of the workpiece to be irradiated with a processing gas, the first filler material, A flattening step of removing at least a part of a portion of the detected material and the second filler formed above the upper surface of the recording element to flatten the surface is performed in this order. And detecting a component of the material to be detected that is removed from the workpiece and scattered in the planarization step. Method of manufacturing a magnetic recording medium characterized by stopping the irradiation of the components of the detection result based in the processing gas 該被 detection material. In claim 1,
In the first filling material film forming step, the first filling material is formed with a thickness equal to or greater than the depth of the recessed portion so as to completely fill the recessed portions of the uneven pattern, and in the planarizing step, A method of manufacturing a magnetic recording medium, wherein irradiation of the processing gas is stopped based on a detection result of a component of a detected material that is removed from the concave portion and scattered among the detecting material. In claim 1 or 2,
In the detected material film forming step, a non-oxide film is formed on the first filler to form the detected material, and as at least one of the first filler and the second filler A method for producing a magnetic recording medium, comprising using an oxide. In claim 3,
In the detecting material film forming step, the detecting material is dispersed on the first filler, and a thin film is formed so as not to completely cover the first filler. A method of manufacturing a magnetic recording medium. In any one of Claims 1 thru | or 4,
A method of manufacturing a magnetic recording medium, comprising: detecting a component of the material to be detected by any one of secondary ion mass spectrometry and quadrupole mass spectrometry in the planarization step.

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