JP2011255653A - Drawing method, method for manufacturing original plate, method for manufacturing stamper, and method for manufacturing information recording disk - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drawing method capable of drawing a fine pattern with high precision on a resist layer, a method for manufacturing an original plate using the same, a method for manufacturing a stamper, and a method for manufacturing an information recording disk.SOLUTION: There is prepared a workpiece 30 including a resist layer support material 34 composed of a material capable of being observed by a scanning electron microscope and a resist layer 36 covering the resist layer support material 34 in a lithographic area EA and formed on the resist layer support material 34 so as not to cover the resist layer support material 34 in at least a part of the inside non-lithographic area NEA1 and the outside non-lithographic area NEA2. The portion exposed from the resist layer 36 in the resist layer support material 34 is observed by the scanning electron microscope, and based on the observation result the position of the focal point of the electron beam is adjusted followed by irradiating the resist layer 36 with the electron beam and exposing the resist layer 36 to light in a predetermined lithographic pattern.

Description

  The present invention relates to a drawing method that can be used for manufacturing an information recording disk, a master disk manufacturing method, a stamper manufacturing method, and an information recording disk manufacturing method.

  Conventionally, a master is used to manufacture an information recording disk such as an optical disk. For example, a resist layer is formed on a substrate such as glass, drawn (exposed) on the resist layer with a pattern corresponding to a pit or groove of an optical disc, and further developed to be either an exposed or non-exposed portion of the resist layer. Is removed to form a resist layer having a pattern corresponding to pits and grooves, and the substrate is etched based on the resist layer to obtain a master having a pattern corresponding to pits and grooves formed thereon. A conductive film is formed by a chemical plating method or a sputtering method on the transfer surface (the surface on which a pattern corresponding to pits or grooves is formed) of this master disk, and further electroplating is performed on the conductive film using the conductive film as an electrode by an electrolytic plating method. A stamper is obtained by forming a layer and peeling these conductive film and electrolytic plating layer together from the master. An optical recording medium substrate on which pits and grooves are formed is obtained by placing the stamper thus obtained in a mold and performing resin molding. In addition, an electroplated conductive layer and an electroplated layer integrally peeled from the master are used as a metal mother, and an electroplated layer is further formed on the metal mother by electroplating, and the electroplated layer is peeled from the metal mother as a stamper. Sometimes used as Further, the stamper may be formed by repeating the electrolytic plating method. The exposed and non-exposed portions in the drawing may be appropriately replaced depending on the resist type (positive type or negative type), the number of times of transfer until a stamper is obtained, and the like.

  In recent years, the recording density of optical discs has been remarkably improved, and the track pitch is several hundred nm or less. For example, the track pitch of an optical disc called Blu-ray Disc (registered trademark) is 320 nm. Along with this, highly accurate drawing is required.

  In recent years, the recording density of magnetic disks such as hard disks has been remarkably improved. In the field of magnetic disks, the data area portion of the recording layer is formed in a pattern corresponding to tracks in order to further improve the recording density. In addition, there has been proposed a discrete track medium or a patterned medium formed with a pattern corresponding to a recording bit (see, for example, Patent Document 1). For example, a resin layer is formed on a continuous film of ferromagnetic material, and a concavo-convex pattern corresponding to a track or a recording bit is transferred to the resin layer by imprinting using a stamper. A recording layer having a pattern corresponding to a track or a recording bit can be formed by etching a continuous film of material. One or more mask layers are formed between the continuous film of the ferromagnetic material and the resin layer, the mask layer is etched based on the resin layer, and the continuous ferromagnetic material is formed based on the mask layer. It has also been proposed to etch the film. It has been proposed to use a master as described above as a stamper for transferring a concavo-convex pattern corresponding to a track or a recording bit to a resin layer, or to obtain such a stamper. In discrete track media and patterned media, track pitches of several tens of nm (for example, 50 nm or less) have been proposed, and drawing with higher accuracy than that of optical discs is required.

  When drawing such a fine pattern, the influence of the wavelength of light used for drawing cannot be ignored, so an electron beam is used for drawing. Further, in order to realize high-precision drawing, it is necessary to accurately align the focus position of the electron beam with the resist layer. An electron beam drawing apparatus usually has a function of a scanning electron microscope (SEM), and a technique for adjusting the focus of an electron beam using the SEM function is known. On the other hand, the surface of the resist layer is excessively flat and is not suitable for SEM observation.

  Therefore, the workpiece to be drawn and the reference sample for adjustment are arranged side by side, the height of the reference sample is adjusted so that the levels of the top surfaces of the two match, and the reference sample is irradiated with an electron beam to irradiate the reference sample. A method is known in which the position of the focal point of the electron beam is adjusted to the level of the upper surface, and the workpiece is moved to the irradiation position of the electron beam instead of the reference sample to perform drawing on the workpiece (for example, Patent Document 2). reference). Also known is a method in which a marking pin is brought into contact with a resist layer of a workpiece to be drawn, a part of the resist layer is mechanically peeled to form a groove, and a focal point is aligned with the edge of the groove. (For example, see Patent Document 3).

JP 2010-049752 A JP 2003-123777 A JP 2006-309821 A

  However, in the method using the reference sample, even if the height of the reference sample for adjustment is adjusted, a deviation of about several μm occurs between the level of the upper surface of the workpiece to be drawn and the level of the upper surface of the reference sample. There was a thing. In the case of drawing a pattern with a track pitch of 100 nm or more, even if such a deviation occurs, there is no practical problem, but it is smaller than 100 nm as in discrete track media and patterned media ( In the case of drawing a track pitch pattern (for example, 50 nm or less), the developed resist layer pattern may have a shape or dimension shift that is unacceptable in practice. Therefore, the pattern of the master disc obtained on the basis of such a resist layer sometimes has a shape and dimensional deviation that is unacceptable in practice.

  In addition, in the method in which a marking pin is brought into contact with the resist layer of the workpiece to be drawn and a part of the resist layer is mechanically peeled off, a part of the peeled resist layer may adhere to the drawing region. In some cases, it was not possible to draw properly according to the original drawing pattern. Therefore, in this case, the developed resist layer pattern may have a shape and size shift which is not practically acceptable, and the master pattern obtained based on such a resist layer may be practically unacceptable. Deviations in shape and dimensions may occur.

  The present invention has been made in view of the above problems, and is a drawing method capable of drawing a fine pattern on a resist layer with high accuracy, a master manufacturing method using the same, a stamper manufacturing method, and an information recording disk It aims at providing the manufacturing method of.

  The present invention is formed of a material that can be observed with a scanning electron microscope, formed in a predetermined annular drawing region, and further formed in a non-drawing region that exists at least one of the inside and outside in the radial direction of the drawing region. A resist layer supporting material and a resist layer formed on the resist layer supporting material so as to cover the resist layer supporting material in the drawing region and not to cover the resist layer supporting material in at least a part of the non-drawing region. A workpiece preparation step for preparing a workpiece, and a portion exposed from the resist layer in a non-drawing region of the resist layer support material is observed with a scanning electron microscope, and an electron beam based on a result of observation with the scanning electron microscope A drawing process including adjusting a focus position and irradiating the resist layer with an electron beam to expose the resist layer with a predetermined drawing pattern. It is those that have achieved the goal.

  In this drawing method, an electron beam is observed by observing the upper surface of a resist layer support made of a material that can be observed with a scanning electron microscope, not the upper surface of a resist layer that is not suitable for observation with a scanning electron microscope. The position of the focal point can be adjusted to the level of the upper surface of the resist layer support material (the lower surface of the resist layer).

  In addition, since the focus of the electron beam is adjusted by directly observing the workpiece to be drawn (the resist layer support material) instead of the reference sample, the position of the focus of the electron beam is set on the resist layer support material of the workpiece. It is possible to reliably match the level of the upper surface (the lower surface of the resist layer).

  In addition, since there is no need to mechanically remove a part of the resist layer by bringing a marking pin into contact with the resist layer to be drawn for observation with a scanning electron microscope, the resist layer can be appropriately applied according to a desired drawing pattern. Can draw.

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

(1) It is made of a material that can be observed by a scanning electron microscope, is formed in a predetermined annular drawing area, and is also formed in a non-drawing area that exists on at least one of the inside and outside in the radial direction of the drawing area. The resist layer support material is formed on the resist layer support material so as to cover the resist layer support material in the drawing region and not to cover the resist layer support material in at least a part of the non-drawing region. A workpiece preparing step for preparing a workpiece including a resist layer, and a portion exposed from the resist layer in the non-drawing region of the resist layer support material is observed with a scanning electron microscope, and the scanning electron microscope is used. Based on the observation result, the position of the focus of the electron beam is adjusted, and the resist layer is irradiated with the electron beam, and the resist layer is irradiated with a predetermined drawing pattern. Drawing method which comprises a drawing step of exposing, the.

(2) In (1), the workpiece preparation step covers the resist layer support material in the drawing region and does not cover the resist layer support material in at least a part of the non-drawing region. A drawing method comprising a resist layer forming step of forming the resist layer on the resist layer supporting material.

(3) A method of manufacturing a master, wherein a master having a transfer surface of a concavo-convex pattern corresponding to the drawing pattern is manufactured using the drawing method of (1) or (2).

(4) In (3), a workpiece further provided with a substrate under the resist layer support material is prepared as the workpiece in the workpiece preparation step, and the resist layer support material etches the substrate. A development step for developing the resist layer after the drawing step, a mask layer etching step for etching the mask layer based on the resist layer, and etching the substrate based on the mask layer And a substrate etching process.

(5) In (3), a workpiece further including a substrate under the resist layer support material is prepared as the workpiece in the workpiece preparation step, and the resist layer is developed after the drawing step A method for manufacturing a master, further comprising: a developing step, and a substrate etching step for etching the resist layer support material and the substrate based on the resist layer.

(6) In (3), the resist layer support material is a substrate, and a development step of developing the resist layer after the drawing step, and a substrate etching step of etching the substrate based on the resist layer, Furthermore, the manufacturing method of the original disk characterized by the above-mentioned.

(7) A stamper having a concavo-convex pattern transfer surface corresponding to the concavo-convex pattern is manufactured using the master manufactured using the master manufacturing method according to any one of (3) to (6). Stamper manufacturing method.

(8) A method for manufacturing an information recording disk, wherein an information recording disk is manufactured using a stamper manufactured by using the stamper manufacturing method of (7).

  In this application, the term “information recording disk” refers to an optical disk, a magnetic disk, a magneto-optical disk, a heat-assisted recording disk that uses both magnetism and heat for information recording, and a micro that uses both magnetism and microwave. It is used in the meaning including the wave assist type recording disk.

  According to the present invention, a fine pattern can be drawn on a resist layer with high accuracy.

Sectional drawing parallel to radial direction and thickness direction which shows typically the structure of the information recording disc manufactured using the drawing method concerning 1st Embodiment of this invention Plan view Flowchart showing an outline of a master manufacturing method for manufacturing the information recording disk using the drawing method Sectional drawing parallel to radial direction and thickness direction schematically showing a workpiece in a state before completion of the original master in which a resist layer support material (mask layer) is formed on a substrate Plan view Sectional drawing parallel to radial direction and thickness direction schematically showing the process of forming a resist layer on the resist layer support material Sectional drawing parallel to radial direction and thickness direction schematically showing the workpiece on which the resist layer has been formed Plan view Side view including a cross-sectional view schematically showing an electron beam drawing apparatus used for drawing the resist layer Sectional drawing parallel to radial direction and thickness direction schematically showing focus adjustment method in drawing process of resist layer of same workpiece Cross-sectional view parallel to radial direction and thickness direction schematically showing drawing on the resist layer Sectional drawing parallel to radial direction and thickness direction schematically showing the workpiece with the resist layer developed Sectional drawing parallel to radial direction and thickness direction schematically showing the workpiece with resist layer support material (mask layer) etched Sectional drawing parallel to radial direction and thickness direction schematically showing the workpiece with the substrate etched Sectional drawing parallel to radial direction and thickness direction schematically showing master disc obtained by removing resist layer support material (mask layer) on same substrate The flowchart which shows the outline | summary of the manufacturing method of the original disk which concerns on 2nd Embodiment of this invention. Sectional drawing parallel to radial direction and thickness direction which shows the to-be-processed body to which the resist layer support material and board | substrate which concern on the 2nd Embodiment were etched The flowchart which shows the outline | summary of the manufacturing method of the original disk which concerns on 3rd Embodiment of this invention. Sectional drawing parallel to radial direction and thickness direction which shows typically the process in which a resist layer is formed into a film on the board | substrate of the to-be-processed object which concerns on the 3rd Embodiment. Sectional drawing parallel to radial direction and thickness direction schematically showing the workpiece on which the resist layer has been formed Sectional drawing parallel to radial direction and thickness direction schematically showing focus adjustment method in drawing process of same resist layer Cross-sectional view parallel to radial direction and thickness direction schematically showing drawing on the resist layer Sectional drawing parallel to radial direction and thickness direction schematically showing the workpiece with the resist layer developed Sectional drawing parallel to radial direction and thickness direction schematically showing the workpiece with the substrate etched Example of SEM image of upper surface of sample resist layer support material of example of the present invention Another example of SEM image of upper surface of resist layer support material of sample of same example Example of SEM image of resist layer after development of sample of same example Example of SEM image of resist layer after development of sample of comparative example

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

  The first embodiment of the present invention is a drawing method used to form a predetermined uneven pattern in an annular recording area RA concentric with the information recording disk 10 in the information recording disk 10 as shown in FIGS. About. In order to understand the first embodiment, first, the structure of the information recording disk 10 will be briefly described.

  The information recording disk 10 is a perpendicular recording type discrete track medium (magnetic disk) in which a central hole 10A is formed. The recording area RA has an annular shape that is concentric with the information recording disk 10, and as shown in FIG. It is divided into a data area DA set in between. Further, the inner area in the radial direction from the recording area RA in the information recording disk 10 is an inner non-recording area NRA1 in which no data or servo signals are recorded. The diameter of the inner non-recording area NRA1 is larger than the diameter of the center hole 10A. Further, the area outside the recording area RA in the radial direction in the information recording disk 10 is also the outer non-recording area NRA2 where no data or servo signals are recorded.

  The information recording disk 10 includes a substrate 12, a soft magnetic layer 14, an orientation layer 16, and a recording layer 18, and these layers are formed on the substrate 12 in this order. In FIG. 1, in order to understand the first embodiment, the thickness of the substrate 12 and each layer is drawn extremely thicker than the actual thickness.

  The recording layer 18 is formed in a pattern corresponding to a track in the data area DA. More specifically, the recording layer 18 is divided into a large number of arc-shaped recording elements corresponding to the track shape in the data area DA. The track pitch is, for example, several tens of nm. In FIG. 1 and FIG. 2, the track shape is drawn extremely larger than the actual (the number of tracks is extremely small) in order to understand the first embodiment. Further, the recording layer 18 is formed in a concavo-convex pattern corresponding to a predetermined servo pattern in the servo area SA. In FIG. 1, for convenience, only the data area DA is shown, and the servo area SA is not shown. Further, although the recording layer 18 is completely exposed in FIG. 1, the concave portions (the concave portions between the recording elements) of the recording layer 18 may be filled with a nonmagnetic filler or the like so that the surface is flattened. Further, a protective layer or a lubricating layer may be formed on the recording layer 18 (and the filler). An underlayer or an antiferromagnetic layer may be formed between the substrate 12 and the soft magnetic layer 14. Further, although the recording layer 18 and the like are formed on only one side of the substrate 12, the recording layer 18 and the like may be formed on both sides of the substrate 12.

  Next, according to the flowchart shown in FIG. 3, a drawing method used to form a concavo-convex pattern corresponding to a track pattern or a servo pattern in the recording area RA of the information recording disk 10 and a master disc using the drawing method are used. A method will be described.

  First, as shown in FIGS. 4 to 8, a workpiece 30 that is a form of a master production process is prepared (S102: workpiece preparation step). The workpiece 30 includes a drawing area EA including an area corresponding to the recording area RA of the information recording disk 10, an inner non-drawing area NEA1 radially inward of the drawing area EA, and a radially outer side of the drawing area EA. It is divided into an outer non-drawing area NEA2. The drawing area EA corresponds to, for example, the recording area RA and a portion near the outer periphery in the inner non-recording area NRA1 and / or a portion near the inner periphery in the outer non-recording area NRA2. Note that the shape of the recording area RA and the shape of the drawing area EA may be the same. Further, the outer diameter of the outer non-rendering area NEA2 is larger than the outer diameter of the outer non-recording area NRA2.

  Specifically, first, as shown in FIGS. 4 and 5, a mask layer (resist layer support material 34) is deposited on the substrate 32 by sputtering or the like (S102A: resist layer support material deposition step). The material of the substrate 32 is glass, Si, glassy carbon, SiC, or the like. The substrate 32 has a thickness of 0.3 to 3 mm. The outer diameter of the substrate 32 is larger than the outer diameter of the substrate 12 of the information recording disk 10. The substrate 32 is not formed with a central hole.

  The mask layer (resist layer support material 34) is made of a material that can be observed with a scanning electron microscope (SEM). The mask layer (resist layer support material 34) is made of a material that functions as a mask in a substrate etching step (S110) described later. Materials that can be observed with a scanning electron microscope are, for example, polycrystalline materials having grain boundaries and materials having a surface arithmetic average roughness Ra of 0.35 nm or more. For example, a film suitable for SEM observation can be formed by setting film forming conditions such as setting the chamber pressure high in sputter film formation. Note that a material having an electrical resistivity of 100 Ωcm or less is preferable from the viewpoint that charge-up due to electrons hardly occurs and observation is easy. Specifically, as the material of the resist layer support material 34, for example, Ni, Si, Ta, Cr, Ti, Mn, Zn, Co, Pt, Au, W, Ag, Al, Cu, C (carbon) or the like is used. be able to. In the first embodiment, as described above, the resist layer support material 34 functions as a mask in the substrate etching step (S110) described later, and therefore the material of the resist layer support material 34 is different from the material of the substrate 32. The thickness of the resist layer support material 34 is 2 to 20 nm. The resist layer support material 34 is formed on the entire surface of the substrate 32. In other words, the resist layer support material 34 is formed in the drawing area EA, and is also formed in the inner non-drawing area NEA1 and the outer non-drawing area NEA2.

  Next, as shown in FIG. 6, the resist layer support material 34 is coated so as to cover the resist layer support material 34 in the drawing area EA and not to cover the resist layer support material 34 in a part of the inner non-drawing area NEA1. A resist layer 36 is formed thereon (S102B: resist layer forming step). Specifically, the liquid material of the resist layer 36 is supplied to a portion slightly inside the outer periphery of the inner non-drawing area NEA1 in the workpiece 30 by spin coating, and the workpiece 30 is rotated to rotate the resist layer 36. A liquid material is caused to flow radially outward by centrifugal force. As a result, as shown in FIGS. 7 and 8, a resist layer 36 is formed in the inner non-drawing area NEA1 excluding the central portion, the drawing area EA, and the outer non-drawing area NEA2. The thickness of the resist layer 36 is 10 to 200 nm. The material of the resist layer 36 is an electron beam resist, and may be a positive type or a negative type.

  Next, using an electron beam drawing apparatus 40 as shown in FIG. 9, the resist layer 36 is irradiated with an electron beam, and the resist layer 36 corresponds to a track pattern or a servo pattern of the recording layer 18 of the information recording disk 10. Exposure is performed with a drawing pattern including a pattern corresponding to the uneven pattern (S104: drawing step). It should be noted that the drawing pattern may be a pattern corresponding only to the concave / convex pattern corresponding to the track pattern or servo pattern of the recording layer 18 of the information recording disk 10.

  The electron beam drawing apparatus 40 controls an electron beam focus position (vertical position in FIG. 9) and an irradiation position (horizontal position in FIG. 9), and an electron beam column 42 that can irradiate an electron beam. And a vacuum chamber 44 provided under the electron beam column 42, and has an SEM function using an electron beam used for exposure (an electron beam irradiated by the electron beam column 42). The electron beam column 42 includes an electron gun 46, a converging lens 48, a blanking electrode 50, an aperture 52, a beam polarizer 54, a non-aberration corrector 56, a focus lens 58, an objective lens 60, Is provided. The vacuum chamber 44 includes a turntable 62 that holds the workpiece 30 and an XY stage 64 that holds the turntable 62 movably in the XY direction (horizontal position in FIG. 9). It has been.

  In this step, first, as shown in FIGS. 9 and 10, a portion exposed from the resist layer 36 in the inner non-drawing region NEA1 of the resist layer support member 34 is observed by SEM using an electron beam used for exposure, and SEM observation is performed. Based on the result, the focus of the electron beam is adjusted. More specifically, the focus position of the electron beam is adjusted to the level of the lower surface of the resist layer 36 (the level of the upper surface of the resist layer support member 34). For example, the operator visually observes the SEM image on the upper surface of the resist layer support material 34 while changing the focus position of the electron beam, and focuses on the position where the SEM image on the upper surface of the resist layer support material 34 becomes clearest.

  Thus, by observing the upper surface of the resist layer support material 34 made of a material capable of SEM observation, not the upper surface of the resist layer 36 that is not suitable for SEM observation, the position of the focus of the electron beam is supported on the resist layer. The level of the upper surface of the material 34 (the lower surface of the resist layer 36) can be adjusted.

  In addition, since the focus of the electron beam is adjusted by directly observing the workpiece 30 (the resist layer support material 34) to be drawn instead of the reference sample, the focus position of the electron beam is set to the upper surface of the resist layer support material 34. It is possible to reliably match the level of (the lower surface of the resist layer 36).

  Next, based on the adjustment of the focal point, as shown in FIG. 11, the resist layer 36 of the workpiece 30 is irradiated with an electron beam so that the resist layer 36 is a track pattern of the recording layer 18 of the information recording disk 10. And exposure is performed with a drawing pattern including a pattern corresponding to an uneven pattern corresponding to a servo pattern. A portion corresponding to the convex portion of the recording layer 18 of the information recording disk 10 in the resist layer 36 according to the material (positive type or negative type) of the resist layer 36 and the number of times of transfer from the master to the production of the stamper. Whether to expose the portion corresponding to the recess or not.

  The focus position of the electron beam is adjusted based on the result of SEM observation of the upper surface of the resist layer support member 34 that is a part of the workpiece 30, and the focus position of the electron beam is adjusted to the upper surface (resist layer) of the resist layer support material 34. Therefore, the resist layer 36 is in accordance with a drawing pattern including a pattern corresponding to a track pattern of the recording layer 18 of the information recording disk 10 and a concavo-convex pattern corresponding to a servo pattern. The exposure can be performed with high accuracy. In addition, since it is not necessary to mechanically peel off a part of the resist layer 36 by bringing a marking pin into contact with the resist layer 36 to be drawn for SEM observation, the resist layer 36 is also in accordance with a desired drawing pattern. Can draw properly. The focus position of the electron beam is adjusted to the level of the lower surface of the resist layer 36. However, if the thickness of the resist layer 36 is in the range of 10 to 200 nm, the resist layer 36 has a high accuracy from the lower surface to the upper surface. It is possible to expose. When the thickness of the resist layer 36 is remarkably thick, for example, the focus position may be corrected so that the position of the focus is adjusted to an intermediate point in the thickness direction of the resist layer.

  Next, the resist layer 36 is developed (S106: development step). Thereby, as shown in FIG. 12, the exposed portion (in the case of positive type) or the non-exposed portion (in the case of negative type) of the resist layer 36 is removed, and the tracks and servo patterns of the recording layer 18 of the information recording disk 10 are removed. A resist layer 36 having a pattern including a concavo-convex pattern corresponding to the concavo-convex pattern corresponding to is formed.

  Next, the mask layer (resist layer support material 34) is etched based on the resist layer 36 (S108: mask layer etching step). As a result, as shown in FIG. 13, the exposed portion of the resist layer support member 34 from the resist layer 36 is removed, and it corresponds to the uneven pattern corresponding to the track pattern or servo pattern of the recording layer 18 of the information recording disk 10. A mask layer (resist layer support material 34) having a pattern including the concavo-convex pattern to be formed is formed. As an etching method, for example, IBE (Ion Beam Etching) using a rare gas such as Ar can be used. Alternatively, the resist layer support material 34 may be etched by RIE (Reactive Ion Etching) using a reactive gas whose etching rate for the material of the mask layer (resist layer support material 34) is higher than the etching rate for the resist layer 36.

Next, the substrate 32 is etched based on the mask layer (resist layer support material 34) (S110: substrate etching step). The etching is stopped when the etching progresses to a position in the middle of the thickness direction of the substrate 32. As a result, as shown in FIG. 14, the exposed portion of the substrate 32 from the mask layer (resist layer support material 34) is removed, and irregularities corresponding to the track pattern and servo pattern of the recording layer 18 of the information recording disk 10 are removed. A substrate 32 having a concavo-convex pattern including the concavo-convex pattern corresponding to the pattern is formed. When the material of the substrate 32 is glass, Si, or SiC, RIE using a fluorine-based gas such as CF ₄ or SF ₆ can be used as an etching method. When the material of the substrate 32 is glassy carbon, for example, RIE using an oxygen-based gas such as O ₂ can be used as an etching method. In this step, the resist layer 36 is completely removed.

  Next, the mask layer (resist layer support material 34) remaining on the convex portions of the substrate 32 is removed by wet etching (S112: resist layer support material removal step). When the material of the mask layer (resist layer support material 34) is Ni, for example, a sulfamic acid solution can be used as the etching solution. As a result, as shown in FIG. 15, a master 70 having a concavo-convex pattern transfer surface including a concavo-convex pattern corresponding to the track pattern of the recording layer 18 of the information recording disk 10 and the concavo-convex pattern corresponding to the servo pattern is completed. .

  Here, a method for forming the recording layer 18 having a concavo-convex pattern corresponding to the track pattern or servo pattern of the information recording disk 10 using the master 70 will be briefly described. First, a conductive film is formed on the transfer surface of the concave and convex pattern of the master 70 by a chemical plating method or a sputtering method, and an electrolytic plating layer is formed on the conductive film by using this conductive film as an electrode. A metal stamper having a concavo-convex pattern transfer surface corresponding to the concavo-convex pattern on the transfer surface of the master 70 can be obtained by integrally peeling the electrolytic plating layer from the master 70. Next, the above-described metal is applied to the resist layer of the workpiece in which the soft magnetic layer 14, the orientation layer 16, the continuous recording layer 18, the mask layer, and the resist layer are formed on the substrate 12 of the information recording disk 10. The stamper is pressed to transfer the uneven pattern on the transfer surface of the metal stamper to the resist layer. By sequentially etching the mask layer and the recording layer 18 based on the resist layer having the concavo-convex pattern, the concavo-convex pattern recording layer 18 corresponding to the track and the servo pattern is formed. In addition, an electrically conductive film and an electrolytic plating layer integrally peeled from the master 70 are used as a metal mother, an electrolytic plating layer is further formed on the metal mother by an electrolytic plating method, and the electrolytic plating layer is peeled off from the metal mother. It may be used as a metal stamper. Further, the metal stamper may be formed by repeating the electrolytic plating method. Further, a resin stamper having a concavo-convex pattern transfer surface corresponding to the concavo-convex pattern of the transfer surface of the master disk 70 is prepared by resin molding by placing a metal stamper in the mold, and the resin stamper is pressed against the resist layer by pressing the resin stamper against the resist layer. The uneven pattern on the transfer surface may be transferred to the resist layer. What is necessary is just to change suitably the exposure part and non-exposure part in drawing according to the frequency | count of the electrolytic plating until obtaining the resist type (positive type or negative type), a stamper, etc.

  Next, a second embodiment of the present invention will be described. In the first embodiment, the mask layer (resist layer support material 34) is etched based on the resist layer 36 (S108), and the substrate 32 is etched based on the mask layer (resist layer support material 34) (S110). . In contrast, in the second embodiment, the resist layer support material 34 does not function as a mask in the substrate etching step (S110). As shown in the flowchart of FIG. 16, the mask layer etching step (S108) is omitted. As shown in FIG. 17, in the substrate etching step (S110), the resist layer support 34 and the substrate 32 are based on the resist layer 36. Etch. In the resist layer support material removing step (S112), the resist layer 36 and the resist layer support material 34 remaining on the convex portions of the substrate 32 are removed. In the resist layer support material removing step (S112), two types of etching solutions corresponding to the resist layer 36 and the resist layer support material 34 may be used. Since other steps are the same as those in the first embodiment, the same elements as those in FIGS.

  Also in the second embodiment, the resist layer support material 34 needs to be made of a material that can be observed with a scanning electron microscope, but the material of the resist layer support material 34 functions as a mask layer for etching the substrate. It need not be a material. Therefore, the range of selection of the material for the resist layer support material 34 can be expanded. As a material of the resist layer support material 34 of the second embodiment, for example, Ni, Si, Ta, Cr, Ti, Mn, Zn, Co, Pt, Au, W, Ag, Al, Cu, C (carbon), Materials such as Si, glassy carbon, and SiC can be used. As the material of the substrate 32, for example, glass, Si, glassy carbon, and SiC can also be used in the second embodiment. Even when the same material as the material of the substrate 32 such as Si, glassy carbon, SiC, or the like is used as the material of the resist layer support material 34, for example, film formation conditions such as setting the chamber pressure high in sputter film formation should be set. Thus, a film having a large surface roughness and suitable for SEM observation can be formed. In the substrate etching step (S110) of the second embodiment, for example, IBE using a rare gas such as Ar can be used. Alternatively, the resist layer support material 34 and the substrate 32 may be etched by RIE using a reaction gas whose etching rate for the material of the resist layer support material 34 and the substrate 32 is higher than the etching rate for the resist layer 36.

  Next, a third embodiment of the present invention will be described. The workpiece 30 according to the first and second embodiments further includes a substrate 32 below the resist layer support material 34. However, the workpiece 80 according to the third embodiment has a resist layer support material 82 as a substrate. Also serves as. The resist layer support material 82 of the third embodiment is also made of a material capable of SEM observation, similar to the resist layer support material 34 of the first and second embodiments. Further, the material of the resist layer support member 82 needs to be a material suitable as a material of the final master 70. As a material of the resist layer support material 82 of the third embodiment, for example, Si, glassy carbon, or SiC can be used.

  As shown in the flowchart of FIG. 18, in the workpiece preparation step (S102) of the third embodiment, the resist layer support material is not formed but only the resist layer is formed. More specifically, as shown in FIGS. 19 and 20, the resist layer 36 is formed directly on the substrate (resist layer support member 82).

  In the drawing step (S104), as shown in FIG. 21, the portion exposed from the resist layer 36 in the inner non-drawing region NEA1 of the substrate (resist layer support member 82) is observed by SEM, and the electron beam based on the result of SEM observation is observed. Adjust the focus position. More specifically, the focus position of the electron beam is adjusted to the level of the lower surface of the resist layer 36 (the level of the upper surface of the substrate (resist layer support member 82)). The substrate (resist layer support material 82) is processed in advance so that the upper surface of the inner non-drawing region NEA1 of the substrate (resist layer support material 82) is rougher than the upper surface of other portions so as to be suitable for SEM observation. You may keep it. For example, a plurality of concave portions are formed in the inner non-drawing area NEA1 of the substrate (resist layer support material 82) by FIB (Focused Ion Beam).

  Next, as shown in FIG. 22, the drawing step (S104) is executed as in the first and second embodiments, and the developing step (S106) is further executed as shown in FIG.

  Next, as shown in FIG. 24, a substrate etching process (S110) is performed. In the substrate etching step (S110) of the third embodiment, the substrate (resist layer support material 82) is etched based on the resist layer 36. Note that the mask layer etching step (S108) is omitted as in the second embodiment.

Further, after the substrate etching step (S110), a resist layer removing step (S114) is executed instead of the resist layer support material removing step (S112). In the resist layer removing step (S114), the resist layer 36 remaining on the convex portions of the substrate (resist layer support member 82) is removed by RIE using a reactive gas such as O ₂ gas. As a result, the same master 70 as in the first and second embodiments is obtained.

  In addition, about the same element as the said 1st and 2nd embodiment, description was abbreviate | omitted suitably using the same code | symbol as FIGS.

  In the third embodiment, since the resist layer support material 82 also serves as a substrate, the configuration of the workpiece 80 is simple and the number of machining steps of the workpiece 80 is small, which contributes to the improvement of production efficiency.

  In the first to third embodiments, the resist layer support material 34 (82) is covered in the drawing area EA in the workpiece preparation step (S102), and the resist layer is partially covered in the inner non-drawing area NEA1. The resist layer 36 is formed on the resist layer support material 34 (82) so as not to cover the support material 34 (82), but the resist layer 36 is formed on the entire surface of the resist layer support material 34 (82). After film formation, part or all of the portion of the inner non-drawing area NEA1 in the resist layer 36 may be removed by exposure and development. In this case, it is not necessary to adjust the focus of the electron beam with high accuracy in part or all of the exposure of the inner non-drawing area NEA1.

  In the first to third embodiments, the portion exposed from the resist layer 36 in the inner non-drawing region NEA1 of the resist layer support material 34 (82) is observed by SEM in the drawing step (S104). After the resist layer 36 is formed in the non-drawing area NEA2, part or all of the portion of the outer non-drawing area NEA2 in the resist layer 36 is removed by exposure and development, and the outer non-drawing of the resist layer support material 34 (82) is performed. A portion exposed from the resist layer 36 in the region NEA2 may be observed with an SEM, and the focus position of the electron beam may be adjusted based on the result of the SEM observation. Also in this case, it is not necessary to adjust the focus of the electron beam with high accuracy in part or all of the exposure of the outer non-drawing area NEA2.

  In the first to third embodiments, the information recording disk 10 has the inner non-recording area NRA1 and the outer non-recording area NRA2, and the workpiece 30 (80) also has the inner non-drawing area NEA1 and the outer non-drawing area. Although it has NEA2, for example, the information recording disc does not have an outer non-recording area, and the workpiece (which is a form in the manufacturing process of the master) does not have an outer non-drawing area. Good. Further, the information recording disc does not have an inner non-recording area, and the workpiece (which is a form in the manufacturing process of the master) may not have an inner non-drawing area. In this case, a portion exposed from the resist layer in the outer non-drawing region of the resist layer support material may be observed by SEM, and the focus position of the electron beam may be adjusted based on the result of this SEM observation.

  In the first to third embodiments, the workpiece 30 (80) and the master disc 70 have the same disk shape as the information recording disc 10, but the shape of the workpiece and the workpiece in the manufacturing process is information. A shape other than the disk shape such as a square may be used as long as the shape includes the recording disk 10.

  In the first to third embodiments, the information recording disk 10 is a perpendicular recording type discrete track medium. However, the information recording disk 10 is an in-plane recording type discrete track medium, a vertical recording type or an in-plane recording type patterned medium. The present invention can also be applied to drawing used to form a concavo-convex pattern in a recording area. In addition, if it is an information recording disk in which a concavo-convex pattern is formed in the recording area, a magneto-optical disk, a heat-assisted recording disk that uses both magnetism and heat for information recording, and a microwave that uses both magnetism and microwave The present invention can also be applied to drawing used for forming a concavo-convex pattern in a recording area of an information recording disk other than a magnetic disk, such as an assist type recording disk or an optical disk.

  The present invention can also be applied to the manufacture of an information recording medium including a step of separating a continuous layer to be processed into a recording element and a non-recording element by ion implantation or a modification process using a reactive gas. For example, the above-mentioned resin stamper or metal stamper is pressed against the resist layer of the workpiece having a structure in which a continuous layer to be processed, a mask layer, and a resist layer are formed, and the uneven pattern on the transfer surface of the stamper is applied to the resist layer. Then, the mask layer is etched on the basis of the resist layer having the concavo-convex pattern, and a portion exposed from the mask layer in the processed layer is subjected to a modification treatment by ion implantation or a reactive gas to thereby remove the processed layer from the recording element. Can be separated into recording elements.

  The present invention is also applied to the manufacture of a magnetic transfer stamper having a concavo-convex pattern transfer surface used as a master information carrier for magnetic transfer for transferring a servo pattern to a magnetic recording medium having a continuous recording layer. Is possible. For example, a magnetic transfer stamper having a concavo-convex pattern transfer surface formed of a ferromagnetic material can be manufactured by forming a ferromagnetic material on the concavo-convex pattern surface of a resin stamper or metal stamper as described above. it can. Further, by using a ferromagnetic material as the metal stamper as described above, a magnetic transfer stamper formed of a ferromagnetic material and having a concavo-convex pattern transfer surface can be manufactured.

Five samples were prepared, and the drawing process (S104) and the developing process (S106) were performed as in the first embodiment. The conditions were as follows.
Substrate 32 material: Si
Diameter of substrate 32: 100 mm
The thickness of the substrate 32: 0.6 mm
Inner non-drawing area NEA1: Radius 0-15mm
Drawing area EA: radius 15 to 35 mm
Outside non-drawing area NEA2: Radius 35-50mm
Resist layer support material 34: Ni
Resist layer support 34 thickness: 4 nm
Resist layer 36 material: positive electron beam resist ZEP520A (manufactured by Nippon Zeon)
Resist layer 36 thickness: 50 nm
Deposition range of resist layer 36: radius 3 to 50 mm
Drawing pattern track pitch: 50 nm
Radial width of exposed area: 10 nm
Radial width of non-exposed part: 40 nm
Electron beam current: 1 nA
Electron beam linear velocity: 100 mm / sec
Developer: Electron beam resist developer ZED-N50 (manufactured by Nippon Zeon)
Developer temperature: 20 ° C
Development time: 1 min

  FIGS. 25 and 26 are examples of SEM images (magnification: 80,000 times) of the upper surface of the resist layer support material 34 in the drawing step (S104), in which the grain boundaries of Ni are observed. FIG. 25 is an example of an SEM image when it is determined that the focus position of the electron beam coincides with the upper surface of the resist layer support material 34. FIG. 26 is an example of an SEM image when it is determined that the focal position of the electron beam does not coincide with the upper surface of the resist layer support material 34.

  FIG. 27 is an example of an SEM image (magnification: 50,000 times) of the resist layer 36 after the development step (S106). In FIG. 27, the white portion is the radial end portion of the convex portion (non-exposed portion) and appears white due to halation. Moreover, the one where the width | variety of radial direction is wide among black parts shows a part inside the edge part of the radial direction in a convex part. Moreover, the narrower one in the radial direction in the black portion indicates a concave portion (a portion that has been exposed and removed by development).

  Based on the SEM images as shown in FIG. 27, the radial widths of the recesses of the resist layers 36 of the five samples were measured. The measurement results are shown in Table 1. In addition, the numerical value shown in Table 1 is an arithmetic average of 10 measurement results in each sample.

[Comparative example]
Compared to the embodiment, the workpiece 30 to be drawn and the reference sample for adjustment are arranged side by side, the height of the reference sample is adjusted so that the levels of the upper surfaces of the two match, and an electron beam is applied to the reference sample. The focus of the electron beam was adjusted to the level of the upper surface of the reference sample by irradiation. Thereafter, the workpiece 30 was moved to the electron beam irradiation position instead of the reference sample, and drawing was performed on the workpiece 30 while maintaining the focal position. The material of the upper surface portion of the reference sample was Au. The other conditions were set to the same conditions as in the above example. Five samples were prepared in the same manner as in the example, and the drawing process (S104) and the developing process (S106) were executed.

  FIG. 28 is an example of an SEM image (magnification: 50,000 times) of the resist layer 36 after the development process (S106) of the sample of the comparative example. Based on the SEM image as shown in FIG. 28, the width in the radial direction of the recesses of the resist layer 36 of the five samples of the comparative example was measured in the same manner as in the above example. The measurement results are also shown in Table 1. Incidentally, the sample whose measurement result is not shown is a sample in which a concave portion is not formed in a part of the portion which should be a concave portion, like a black dot portion shown in FIG.

  As shown in Table 1, in the comparative example, the resist layer 36 having a desired pattern was formed in three of the five samples, but in the two samples, the resist layer 36 was formed as shown in FIG. The recess was not formed in a part of the portion which should be the recess of the layer 36. If the electron beam focal point is intentionally deviated from the resist layer by about 2 μm, a concave portion is formed in a part of the resist layer which should be a concave portion in the same manner as the two samples of the comparative example. It has been confirmed that it is not formed. In the two samples of the comparative example, the upper surface level of the workpiece 30 to be drawn and the reference sample for adjustment was shifted, so that the exposure was partially inappropriate and the portion of the resist layer 36 that should be a recess It is considered that no recess was formed in a part of this.

  On the other hand, in the example, as shown in FIG. 27, the resist layer 36 having a desired pattern was formed in all five samples. That is, by directly SEM observing the workpiece 30 (the resist layer support material 34) to be drawn and adjusting the focus position of the electron beam, a resist layer having a track pitch pattern smaller than 100 nm can be obtained with high accuracy. It was confirmed that it can be formed.

  Further, as shown in FIGS. 25 and 26, by observing the upper surface of the resist layer support material 34 with an SEM, the position of the focal point of the electron beam becomes the level of the upper surface of the resist layer support material 34 (the level of the lower surface of the resist layer 36). ), It was confirmed that it can be clearly identified.

  The present invention can be used, for example, for manufacturing information recording disks such as discrete track media and patterned media.

DESCRIPTION OF SYMBOLS 10 ... Information recording disk 12 ... Substrate 14 ... Soft magnetic layer 16 ... Orientation layer 18 ... Recording layer 30, 80 ... Workpiece 32 ... Substrate 34 ... Mask layer (resist layer support material)
36 ... Resist layer 40 ... Electron beam drawing apparatus 42 ... Electron beam column 44 ... Vacuum chamber 70 ... Master disc 82 ... Substrate (resist layer support material)
RA ... Recording area NRA1 ... Inner non-recording area NRA2 ... Outer non-recording area DA ... Data area SA ... Servo area EA ... Drawing area NEA1 ... Inner non-drawing area NEA2 ... Outer non-drawing area S102 ... Workpiece preparation step S102A ... Registration Layer support material film forming step S102B ... Resist layer film forming step S104 ... Drawing step S106 ... Development step S108 ... Resist layer support material (mask layer) etching step S110 ... Substrate etching step S112 ... Resist layer support material removing step S114 ... Resist layer Removal process

Claims (8)

Resist layer support made of a material that can be observed by a scanning electron microscope, formed in a predetermined annular drawing region, and also formed in at least one of the drawing region on the inner side and the outer side in the radial direction A resist layer formed on the resist layer support material so as to cover the material and the resist layer support material in the drawing region, and not to cover the resist layer support material in at least a part of the non-drawing region; A workpiece preparation step of preparing a workpiece including:
A portion exposed from the resist layer in the non-drawing region of the resist layer support material is observed with a scanning electron microscope, and an electron beam focus position is adjusted based on a result of observation with the scanning electron microscope. And a drawing step of exposing the resist layer to a predetermined drawing pattern. In claim 1,
The workpiece preparation step covers the resist layer support material so as to cover the resist layer support material in the drawing region and not cover the resist layer support material in at least a part of the non-drawing region. A drawing method comprising a resist layer forming step of forming the resist layer.   A method for producing a master, comprising producing a master having a transfer surface of a concavo-convex pattern corresponding to the drawing pattern using the drawing method according to claim 1. In claim 3,
In the workpiece preparation step, a workpiece further comprising a substrate under the resist layer support material is prepared as the workpiece, and the resist layer support material is a mask layer for etching the substrate,
A development step of developing the resist layer after the drawing step; a mask layer etching step of etching the mask layer based on the resist layer; and a substrate etching step of etching the substrate based on the mask layer. Furthermore, the manufacturing method of the original disk characterized by the above-mentioned. In claim 3,
Preparing a workpiece further comprising a substrate under the resist layer support material as the workpiece in the workpiece preparation step;
A method of manufacturing a master, further comprising: a developing step of developing the resist layer after the drawing step; and a substrate etching step of etching the resist layer support material and the substrate based on the resist layer. In claim 3,
The resist layer support is a substrate;
A method of manufacturing a master, further comprising: a developing step of developing the resist layer after the drawing step; and a substrate etching step of etching the substrate based on the resist layer.   7. A stamper manufacturing method, wherein a stamper having a concavo-convex pattern transfer surface corresponding to the concavo-convex pattern is manufactured using the master disc manufactured using the master disc manufacturing method according to claim 3.   An information recording disk manufacturing method, wherein an information recording disk is manufactured using a stamper manufactured using the stamper manufacturing method of claim 7.