JP2012155015A - Pattern forming method, method for manufacturing magnetic recording medium and method for manufacturing lsi - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pattern forming method and a method for manufacturing a magnetic recording medium capable of shortening the time required for forming a pattern.SOLUTION: A resist is coated on a substrate on which a hard mask is deposited to form a resist pattern and the hard mask is etched using the resist pattern as a mask to form a hard mask pattern. A resist is coated on the hard mask and electron beam lithography is performed to form a second resist pattern. The hard mask is etched using the second resist pattern as a mask to form a second hard mask pattern.

Description

  Embodiments described herein relate generally to a pattern forming method, a magnetic recording medium manufacturing method, and an LSI manufacturing method.

  In some cases, a patterned media of a magnetic recording device such as a hard disk drive or a fine semiconductor pattern of an LSI is formed by using an imprint technique.

  In order to produce a patterned media master, a resist pattern is formed on a Si substrate by electron beam lithography, and then a Ni film is embedded in the pattern opening by sputtering and plating. Subsequently, after bonding the Ni film to the support plate, the Ni film and the support plate are peeled off from the resist pattern, thereby producing a Ni father master. A mother master can be made by an imprint process using the father master, and a plurality of stampers can be made. Finally, a large number of media (magnetic recording media) can be made using the stamper.

  However, in this type of method, it is necessary to draw a pattern on the entire surface of the disk using an electron beam drawing apparatus in order to produce the father master, and it takes a lot of time to form the father master. Furthermore, when changing the pattern, it is necessary to redraw the changed pattern on the entire surface of the disk by using the electron beam drawing apparatus. Therefore, it takes much time to change the pattern.

  The same problem as described above also occurs when a fine semiconductor pattern of LSI (Large Scale Integration) is formed by using the imprint technique. That is, if a pattern is to be formed on the entire LSI area using the imprint master, the entire pattern needs to be formed on the imprint master. An electron beam lithography apparatus is also used to form such a pattern. Therefore, it takes much time to form the pattern.

JP 2005-1000049 A JP 2008-055908 A

  The problem to be solved by the present invention is to provide a pattern formation method and a method for manufacturing a magnetic recording medium that reduce the time required for pattern formation.

  One embodiment of the present invention is a method of forming a hard mask on a substrate, applying a first resist on the hard mask, and exposing the first resist so that a part of the upper surface of the hard mask is exposed. Forming a first resist pattern; and etching the exposed hard mask until the substrate surface is exposed using the first resist pattern as a mask to form a first hard mask pattern on the hard mask. A step of removing the first resist; applying a second resist on the hard mask and the substrate; and drawing the second resist on a region where the hard mask exists with an electron beam And etching the second resist at the position where the electron beam is drawn so that the hard mask is exposed. Forming a second resist pattern on the resist, and etching the exposed hard mask using the second resist pattern as a mask to form a second hard mask pattern on the hard mask. It is characterized by.

The figure which shows the manufacturing process of the father original disk concerning embodiment. The figure which shows the pattern formation method concerning embodiment. The figure which shows the pattern formation method concerning embodiment. The figure for demonstrating the area | region which irradiates an electron beam in the pattern formation method concerning embodiment. The figure which shows the pattern formation method concerning embodiment. The figure which shows the pattern formation method concerning embodiment. The figure which shows the pattern formation method concerning embodiment. The figure which shows the pattern formation method concerning embodiment. The figure which shows the pattern formation method concerning embodiment. The figure which shows the pattern formation method concerning embodiment. 1 is a perspective view showing an example of a configuration of a hard disk drive (magnetic recording / reproducing apparatus) using a patterned medium according to an embodiment. The figure which shows the track | orbit of the magnetic head concerning embodiment. The figure which shows the state by which the magnetic body concerning embodiment is arranged in circular arc shape. The top view which shows schematic structure of the patterned media concerning embodiment. The figure which shows the arrangement | positioning relationship of the servo data part in the sector concerning embodiment, and a recording data part. The flowchart which shows an example of the manufacture procedure of the master for patterned media concerning embodiment. The figure which shows the process of forming the pattern for a sector identification in the sector identification area | region concerning embodiment. The top view which shows the imprint father master disk for common sectors concerning embodiment. The figure which shows the board | substrate for pattern preparation concerning embodiment. The figure which shows an example of the manufacturing process of the stamper concerning embodiment. The figure which shows an example of the manufacturing process of the magnetic-recording medium concerning embodiment. The figure which shows an example of the manufacturing process of LSI concerning embodiment. The figure which shows an example of the manufacturing process of LSI concerning embodiment.

  The details of the present invention will be described below with reference to the illustrated embodiments.

(First embodiment)
FIG. 1 is a diagram showing a father master manufacturing process performed prior to an imprint master manufacturing process.

  First, as shown in FIG. 1A, a sample is prepared by applying a positive resist 32 such as a PMMA resist on a substrate 31 (for example, a Si substrate), and a desired pattern is drawn by an electron beam drawing apparatus. Thereafter, the resist 32 is developed to form a resist pattern as shown in FIG. Subsequently, as shown in FIG. 1C, a Ni film 33 is formed on the surface of the resist 32 and the exposed surface of the substrate by sputtering, and then a Ni film 34 is formed by plating as shown in FIG. And flatten the surface.

  Next, after the Ni film 34 is bonded to a support plate (not shown), the Ni films 33 and 34 are peeled off from the resist 32 and the substrate 31 as shown in FIG. Thereby, the father master 30 is produced. In the following description, it is assumed that thermal imprinting is performed using the father master, but UV imprint using a material such as glass that transmits ultraviolet light as the father master 30 and a material having ultraviolet light curability is used. Can also be used. In such a case, for example, Ni is replaced with glass.

  2 to 3 are diagrams showing a pattern forming method according to the first embodiment. First, as shown in FIG. 2A, a hard mask 42 is formed on the surface of a substrate 41, and further a material film having the characteristics of a positive resist such as a PMMA (Poly methyl methacrylate) resist, for example. A material coated with a resist 43 is prepared. The substrate 41 is a conductor substrate made of a material having a finite resistance, such as a silicon substrate doped with impurities. The hard mask 42 is made of, for example, a titanium (Ti) thin film (for example, 10 nm thick) in consideration of the selection ratio with the substrate 41. The substrate 41 on which the hard mask 42 and the resist 43 are stacked is imprinted by the thermal imprint method using the father master 30. As a result, as shown in FIG. 2B, the irregularities formed on the father master 30 are transferred to the resist 43 to form a resist pattern. At this time, the hard mask 42 may be exposed at the place pressed by the convex portion of the father master 30, but the resist 43 may remain as a residue on the hard mask 42. Therefore, ashing may be performed in order to remove the residue of the resist 43 and expose the surface of the hard mask 42 corresponding to the convex portion of the father master 30. At the time of ashing, the convex shape formed on the resist 43 corresponding to the concave portion of the father master 30 is adjusted so as not to disappear. For ashing, for example, oxygen ashing is used. Note that the process of removing the residue of the resist 43 and the process of etching the hard mask 42 later may be performed continuously.

  Next, the hard mask 42 is etched using the resist 43 as a mask, and then the resist 43 is removed (FIG. 2C). When titanium is used as the hard mask 42, dry etching using a mixed gas of CF4 and oxygen can be used for etching. The resist 43 is removed by oxygen ashing or a wet process. When this step is completed, a shape corresponding to the uneven shape formed on the father master 30 is formed on the hard mask 42.

  The hard mask pattern is changed by etching a part of the hard mask from the hard mask 42 having the pattern thus formed. For this purpose, first, a resist 44 for electron beam drawing is applied so as to cover the hard mask 42 and the substrate 41. A state where the resist 44 is applied is shown in FIG. The imprint resist and the electron beam drawing resist may be made of the same material or different materials. For example, when a material having higher sensitivity than the imprint resist is used as the resist for electron beam drawing, the time required for the step of irradiating the electron beam described later can be shortened.

  Next, as shown in FIG. 2E, an electron beam is irradiated onto the resist 44 positioned above the hard mask 42 to be etched using an electron beam drawing apparatus. Thereafter, through a development process, a resist pattern as shown in FIG. 3F is formed. By this step, a part of the hard mask 42 is exposed.

  The electron beam irradiation may be performed over a region wider than the upper portion of the hard mask to be etched because strict accuracy is required if the upper portion of the hard mask to be etched is irradiated. The wide area may be a width that does not irradiate the hard mask pattern that is not etched with the electron beam. FIG. 4 is a diagram for explaining a region irradiated with an electron beam. FIG. 4 illustrates a state in which a part of the substrate 41 on which the resist pattern is formed as viewed in FIG. In this example, a hard mask 42a to be etched and a hard mask 42b that is not etched are formed so as to surround it. Although the hard mask 42b is covered with the resist 44, it is shown for explanation. In such a case, a region where the electron beam can be irradiated to expose the hard mask 42a to be etched is a region A where the electron beam is not irradiated to the hard mask 42b which is not etched. FIG. 3F shows an example in which an electron beam is irradiated over a wider area than the area on the hard mask to be etched, and not only a part of the hard mask 42 but also a part of the substrate 41 is exposed. Is shown.

  After the resist pattern is formed as shown in FIG. 3F, the exposed hard mask 42 is etched using the resist 44 as a mask (FIG. 3G), and the resist 44 is removed (FIG. 3H). Thereby, a part of the hard mask pattern of the imprint master can be changed.

Next, as shown in FIG. 3I, the substrate 41 is etched using the hard mask 42 as a mask, thereby forming a pattern structure on the substrate 41. For etching the substrate 41, for example, a fluorine-based etching gas such as CF ₄ is used. Thereafter, the hard mask 42 is removed as shown in FIG. 3J, and a metal film (Ni film) 45 is sputtered as shown in FIG. 3K to form a metal film. As a result, the imprint master 40 can be produced. Note that the step of removing the hard mask 42 shown in FIG. 3J and the step of forming the metal film shown in FIG. 3K may be omitted. Finally, as shown in FIG. 3I, a hard mask can be left after the substrate etching and used as a light-shielding film in UV imprinting.

  According to the pattern forming method according to the present embodiment, if the repetitive pattern included in the imprint master is formed as the pattern of the father master, and the father master is repeatedly imprinted, the entire imprint master Rather than forming a pattern by drawing, the time required for producing the imprint master can be shortened.

  Further, according to the pattern forming method according to the present embodiment, a substrate on which a hard mask pattern is formed as shown in FIG. Therefore, for example, when changing the pattern of the imprint master, a hard mask as shown in FIGS. 2 (d) to 3 (h) is used by using a substrate as shown in FIG. 2 (c). An arbitrary portion can be etched to obtain a desired hard mask pattern, and an imprint master after changing the pattern can be easily produced.

(Second Embodiment)
5 to 6 are views showing a pattern forming method according to the second embodiment. The second embodiment is a manufacturing process when a substrate (for example, a quartz substrate) that is an insulating material is used. When an insulating material is used as the substrate, a conductive film made of a material having a high etching selectivity with the hard mask material is formed below the hard mask so that the surface is not charged during electron beam irradiation. It is desirable. For example, titanium whose conductivity is increased by doping titanium as a hard mask and impurities as a conductive film can be used.

  Hereinafter, the pattern forming method according to the second embodiment will be described with reference to FIGS. However, the steps (a) to (h) of the pattern forming method according to the second embodiment are different in that the conductive film is formed between the insulator substrate and the hard mask, but the first Since it is the same process as that of the embodiment, detailed description is omitted. The resist will be described assuming that a positive resist such as a PMMA resist is used.

  In the pattern forming method of the second embodiment, a sample in which a conductive film 52, a hard mask 42, and a resist 43 are stacked on an insulator substrate 51 as shown in FIG. When this insulator substrate 51 is imprinted using the father master 30, a resist pattern is formed as shown in FIG. Here, as described in the first embodiment, ashing for removing the residue of the resist 43 may be performed.

  Then, when the hard mask 42 is etched using the resist 43 as a mask to remove the resist, a hard mask pattern is formed on the conductive film 52 as shown in FIG. Then, a resist 53 for electron beam drawing is applied on the conductive film 52 and the hard mask pattern (FIG. 5D), and a specific pattern is drawn on the resist 53 using an electron beam drawing apparatus (FIG. 5). (E)). At this time, since the conductive film 52 is formed over the insulator substrate 51, the surface of the insulator substrate 51 can be prevented from being charged even when the electron beam is irradiated.

  Next, a resist pattern as shown in FIG. 6F is formed through a development process, and hard mask etching is performed using the resist 53 as a mask (FIG. 6G), and the hard mask 42 not masked by the resist 53 is removed. Remove. Thereafter, the resist 53 is removed (FIG. 6H). When titanium is used as the hard mask 42, dry etching using a mixed gas of CF4 and oxygen can be used for etching. The resist 43 is removed by oxygen ashing or a wet process.

Then, as shown in FIG. 6 (i), the conductive film 52 and the insulator substrate 51 are etched using the hard mask 42 as a mask to form a pattern structure on the insulator substrate 51. For etching the substrate 51, for example, a fluorine-based etching gas such as CF ₄ is used. Thereafter, the conductive film 52 and the hard mask 42 are removed as shown in FIG. 6 (j), and the Ni film 45 is sputtered onto the insulating substrate 51 as shown in FIG. 6 (k) to form a metal film. To do. Thereby, the imprint master disc 50 can be produced. Note that the step of removing the conductive film 52 and the hard mask 42 shown in FIG. 6J and the step of forming the metal film shown in FIG. 6K may be omitted. Finally, as shown in FIG. 6I, the hard mask 42 or the conductive film 52 can be left after the substrate etching, and the hard mask 42 or the conductive film 52 can be used as a light-shielding film in UV imprinting.

  In the manufacturing process of the imprint master according to the present embodiment, even if an insulator substrate is used as the substrate, the time required to manufacture the imprint master having a repetitive pattern can be reduced, and the process illustrated in FIG. Thus, since the substrate on which the hard mask pattern is formed can be prepared in advance, it is easy to change the pattern of the imprint master.

(Third embodiment)
In the pattern forming method according to the third embodiment, a substrate that is an insulating material (for example, a quartz substrate) is used, but a conductive film is not provided on the substrate, but the resist surface used for electron beam drawing is charged. Applying a protective film avoids charging of the substrate surface. The material of the antistatic film is, for example, a water-soluble conductive polymer. In the third embodiment, chromium is used for the hard mask, chlorine gas is used for hard mask etching, and a mixed gas of CF ₄ and oxygen is used for etching the insulator substrate.

  7 to 8 are diagrams showing a pattern forming method according to the third embodiment. In the pattern forming method according to the present embodiment, a sample in which a hard mask 56 and a resist 43 having the characteristics of a positive resist such as a PMMA resist are formed on an insulator substrate 51 as shown in FIG. Is used. When a sample in which the hard mask 56 and the resist 43 are formed on the insulator substrate 51 is imprinted by the thermal imprint method using the father master 30, as shown in FIG. The irregularities formed on the master 30 are transferred to the resist 43 to form a resist pattern. Here, as described in the first embodiment, ashing for removing the residue of the resist 43 may be performed.

  Then, the hard mask 56 is etched using the resist 43 as a mask. Chlorine gas is used for hard mask etching. After a hard mask pattern is formed on the insulator substrate by hard mask etching as shown in FIG. 7C, a resist 53 for electron beam drawing is applied, and an antistatic film 54 is applied thereon (FIG. 7). (D)). Then, an electron beam is irradiated from the antistatic film 54 to a specific pattern position (FIG. 7E). Thereafter, the antistatic film 54 is removed by rinsing with pure water, for example. As described above, by applying the antistatic film 54 at the time of electron beam drawing, a resist pattern can be formed as shown in FIG. 8F while preventing the surface of the insulating substrate 51 from being charged. As described in the first embodiment, at the time of electron beam writing, writing may be performed for a width wider than the width of the hard mask to be etched.

  After forming a resist pattern as shown in FIG. 8F, hard mask etching using chlorine gas is performed (FIG. 8G), and the resist 53 is removed (FIG. 8H). Thereby, a part of the hard mask pattern can be changed.

Next, as shown in FIG. 8I, the substrate 51 is etched using the hard mask 56 as a mask to form a pattern structure on the substrate 51. For the etching of the substrate 51, for example, a mixed gas of CF ₄ and oxygen is used. Thereafter, the hard mask 56 is removed as shown in FIG. 8 (j), and the Ni film 45 is sputtered as shown in FIG. 8 (k) to form a metal film. Thereby, the imprint master disc 50 can be produced. Note that the step of removing the hard mask 56 shown in FIG. 8J and the step of forming the metal film shown in FIG. 8K may be omitted.

  In the pattern formation method according to the present embodiment, an insulator substrate is used as a substrate, and even if the conductive film is not formed on the insulator substrate in advance, charging to the surface of the insulator substrate during electron beam drawing is prevented. Thus, the same effect as the pattern forming method described in the second embodiment can be obtained.

(Fourth embodiment)
9 to 10 are diagrams showing a pattern forming method according to the fourth embodiment. In the fourth embodiment, after a resist pattern is formed by electron beam lithography, a hard mask pattern is added at a desired position by forming a hard mask.

  Here, it is assumed that an imprint process using the father master 30 is performed on the insulator substrate 51 on which the conductive film 52 and the hard mask 42 are formed using a substrate (for example, a quartz substrate) that is an insulating material. . Further, it is assumed that titanium is used as a hard mask and silicon is used as a conductive film.

  Since the processes shown in FIGS. 9A to 9D and FIGS. 10I to 10J are the same as the pattern forming method according to the second embodiment, detailed description thereof is omitted. In the fourth embodiment, after applying a resist 53 so as to cover the hard mask 42 and the conductive film 52 on which a pattern is formed as shown in FIG. 9D, an electron beam is applied to the position where the hard mask is added. Irradiate (FIG. 9E). Then, a resist pattern as shown in FIG. 10F is formed through a development process.

  Next, the hard mask 42 is formed by sputtering or the like (FIG. 10G). When the resist 53 is removed, the hard mask 42 on the resist 53 is removed together with the resist 53, and the hard mask 42 on the conductive film 52 is removed. Not removed. Therefore, as shown in FIG. 10H, a hard mask pattern in which the hard mask 42 is added at a desired position can be formed.

  As described above, in the pattern forming method according to the fourth embodiment, the hard mask pattern can be changed by adding the hard mask at a desired position.

  In the description of the fourth embodiment, the case where the conductive film is formed on the insulator substrate has been described as an example. However, as described in the first embodiment, the conductor substrate may be used. As described in the third embodiment, an antistatic film may be applied to the resist surface used for electron beam drawing.

  Further, the hard mask film formation process described in the fourth embodiment and the hard mask etching process described in the first to third embodiments may be combined. If a substrate having a hard mask pattern (for example, the state shown in FIG. 9C or FIG. 10H) is prepared in advance by combining the hard mask deposition process and the etching process, The hard mask pattern can be changed freely.

(Application example for manufacturing disc-shaped patterned media)
The method for manufacturing an imprint master according to the first to fifth embodiments can be applied to manufacturing a disk-shaped patterned medium. As an example, a manufacturing process in the case where the pattern forming method according to the first embodiment is applied to patterned media manufacturing will be described.

  FIG. 11 is a perspective view showing an example of the configuration of a hard disk drive (magnetic recording / reproducing apparatus) 150 using patterned media. As shown in FIG. 11, the magnetic recording / reproducing apparatus 150 is an apparatus using a rotary actuator. In the figure, a recording medium disk (magnetic recording medium) 180 is mounted on a spindle motor 160, and the direction of arrow A is driven by a motor (not shown) that responds to a control signal from a drive device control unit (not shown). Rotate to. The magnetic recording / reproducing apparatus according to the present embodiment may include a plurality of recording medium disks 180.

  When the recording medium disk 180 rotates, the pressure applied by the suspension 154 balances with the pressure generated on the medium facing surface (also referred to as ABS) of the head slider, so that the medium facing surface of the head slider extends from the surface of the recording medium disk 180. It is held with a predetermined flying height.

  The suspension 154 is connected to one end of an actuator arm 155 having a bobbin portion for holding a drive coil (not shown). A voice coil motor 156, which is a kind of linear motor, is provided at the other end of the actuator arm 155. The voice coil motor 156 includes a drive coil (not shown) wound around the bobbin portion of the actuator arm 155, and a magnetic circuit composed of a permanent magnet and a counter yoke arranged so as to sandwich the coil. be able to.

  The actuator arm 155 is held by ball bearings (not shown) provided at two locations above and below the bearing portion 157, and can be freely rotated and slid by a voice coil motor 156. As a result, the magnetic recording head can be moved to an arbitrary position on the recording medium disk 180.

  In the magnetic recording / reproducing apparatus 150 having such a configuration, as shown in FIG. 12, since the track of the magnetic head draws an arc, the boundary of each sector is also a part of the arc. In FIG. 12, R1 is the outer diameter of the recording medium disk 180, R2 is the inner diameter of the recording medium disk 180, and R3 is the rotation radius of the magnetic head. In addition, since the angle formed by the head in the radial direction differs depending on the radius, the recording pattern also has a different inclination with respect to the radial direction depending on the radial position, as shown in FIGS. In FIG. 13, the upper side is the outer area of the recording medium disk 180 (area where the distance from the disk center is long), and the lower side is the inner area of the recording medium disk 180 (area where the distance from the disk center is short). For convenience, the following description will be made assuming that the sector shape is a part of a simple sector.

  FIG. 14 is a plan view showing a schematic configuration of the disc-shaped patterned medium according to the present example. The disc-shaped recording medium disk 180 is divided into a plurality of sectors in the circumferential direction. For example, it is divided into 256 sectors from sector 0 to sector 255. The shape of the sector boundary is usually an arc shape because of the trajectory of the signal detection head, but for the sake of simplicity, the description will be made below as a straight line.

  FIG. 15 is an enlarged view of the vicinity of the boundary between adjacent sectors, and is a diagram showing the arrangement relationship between the servo data portion and the recording data portion in the sector. The sector 200 is divided into a servo data area 210 in which a servo pattern is formed and a recording data area 220 for storing recording data. The servo data area 210 further includes a preamble pattern 211 for rotation control and a sector identification. It is divided into a sector identification pattern 212, a track information pattern 213 for identifying a track in the radial direction, and a burst pattern 214 for aligning the track position. When the recording data area 220 is a continuous track, it becomes a so-called discrete track medium, and when it has a shape divided for each bit, it becomes a so-called bit patterned medium. This embodiment can be applied to any medium.

  Next, the manufacturing method of the patterned media master according to this example will be described with reference to the flowchart of FIG.

  In a semiconductor process, a certain pattern may be repeatedly formed on a Si wafer. In such a case, a so-called step-and-repeat method is known in which a unit pattern is transferred a plurality of times. However, this method cannot be directly applied to patterned media. This is because the patterns of each sector are similar, but the address portions are different. Therefore, if applied simply, division patterns corresponding to the number of sectors are necessary, and it is difficult to obtain the advantages of the process shortening time. Therefore, the address part is divided into a part common to each sector and a part to be additionally processed, and the additional processing part is reduced as much as possible to greatly reduce the time.

  First, a common sector imprint father master corresponding to one (or a plurality of) sectors is produced by electron beam lithography (step S101). That is, pattern data for one sector portion of the patterned media pattern is prepared.

  Specifically, a resist is applied to the imprint substrate, and drawing is performed using an electron beam drawing apparatus. At this time, it is desirable to use a vector scan type drawing apparatus using an XY stage as the electron beam drawing apparatus. This is because, in an apparatus having a uniaxial parallel movement and a rotary stage, an area where no pattern exists also passes through the electron beam drawing possible area, resulting in dead time. A positive resist is used as the resist. A pattern drawn using an electron beam drawing apparatus is a pattern in which a common part of each sector is formed. A pattern used for sector identification that is not common to each sector (hereinafter referred to as a sector identification pattern) A pattern in which only the common part of the sector identification pattern is formed. For example, as shown in FIG. The pattern determined in this way is called a common sector pattern.

  In the following, through the process of manufacturing the father master described with reference to FIG. 1, the imprint father master for the common sector having the common sector pattern is manufactured. The formation of the dot structure is not limited to electron beam drawing, and for example, a process using a self-organizing material can be used.

  Next, imprinting is repeated in the circumferential direction using the common sector imprint father master on the pattern production substrate to form a common sector pattern in all sectors (S102). At the time of imprinting, alignment is performed using marks provided on the father master and the pattern production substrate.

  FIG. 18 is a plan view showing an imprint father master for common sector. In the imprint father master 230 for common sector made of Ni, a common sector pattern 236 for one sector is formed in a fan-shaped region. Further, at the periphery of the master 230, marks 237 for alignment in the circumferential direction and the radial direction are provided in at least two locations, and alignment is performed when imprinting on the disk-shaped substrate. Is possible. In addition, it is also effective in increasing the alignment accuracy to form an alignment pattern such as a warnier pattern at a connection portion between adjacent sectors.

  FIG. 19 is a diagram showing a pattern production substrate. An alignment mark 290 is provided on the pattern production substrate 241 so as to correspond to the alignment mark 237 of the imprint father master 230 for the common sector. The mark 290 is used as an alignment mark at the time of imprinting, and also as an alignment mark at the time of electron beam drawing, focused ion beam processing, etching, and imprinting for forming a sector identification pattern.

  For alignment, an optical alignment technique may be used. Thereby, alignment of the father master 230 and each sector of the pattern production substrate 241 can be performed with high accuracy. In the present embodiment, three marks 290 are arranged in each sector, but at least two marks 290 are sufficient.

  After imprinting on the substrate for pattern production, as described in FIGS. 2A to 2C, the hard mask is etched using the formed resist pattern as a mask to remove the resist. A hard mask pattern having a common sector pattern is formed on the substrate. If a large number of substrates on which this common sector pattern is formed are prepared and stored, and if necessary, the following process is performed, the occupancy time of the imprint apparatus for the master production process can be shortened. It takes a long time to use the printing apparatus for product manufacturing.

  Subsequently, in step S103 of FIG. 16, a mother master disc (patterned media master disc) 301 is produced by forming different sector identification patterns for each sector. When step S102 is completed, a hard mask pattern of a common sector pattern is formed on the substrate, as shown in FIG. As shown in FIG. 17C, the common sector pattern is cut according to a certain rule, thereby forming a sector identification pattern different for each sector. In order to make a cut in the hard mask pattern, as described in FIGS. 2D to 3H, after removing the imprint resist, a resist for electron beam lithography is applied to the substrate, and sector identification is performed. A resist pattern is formed by irradiating an electron beam onto a portion where information is to be formed and passing through a development process, and the hard mask is etched using the resist pattern as a mask.

  Next, in step S104 in FIG. 16, a plurality of media masters (stampers) are produced by imprinting using the mother master 301. FIG. 20 is a diagram showing a manufacturing process of the stamper of this example.

  First, as shown in FIG. 20 (l), a disk-shaped substrate 341 coated with a resist 342 having the characteristics of a positive resist such as a PMMA resist is prepared, and a thermal imprint method using a mother master 301 is prepared. By imprinting, a pattern as shown in FIG. 20 (m) is formed.

  Next, as shown in FIG. 20 (n), a Ni film 343 is formed by sputtering on the surface of the resist 342 and the exposed surface of the substrate 341. Then, as shown in FIG. To flatten.

  Next, after attaching a support plate (not shown) to the Ni film 344, the Ni films 343 and 344 are peeled off from the resist 342 and the substrate 341 as shown in FIG. As a result, the patterned media master (stamper) 350 is duplicated. In order to produce a stamper from the mother master, not only the imprint method but also an electroforming method can be used.

  When the stamper is manufactured, a large number of media (magnetic recording media) can be manufactured by imprinting using the stamper (step S105 in FIG. 16). FIG. 21 is a diagram showing a manufacturing process of the magnetic recording medium of this example.

  As shown in FIG. 21 (q), a sample having a magnetic film 362 formed on a substrate 361 and a resist film 363 formed thereon is imprinted using a stamper 350, whereby FIG. A resist pattern as shown in r) is formed.

  Next, as shown in FIG. 21S, after the magnetic film 362 is selectively etched by RIE (Reactive Ion Etching) using the pattern of the resist 363 as a mask, the resist film 363 is shown in FIG. Remove. Thereafter, as shown in FIG. 21 (u), a protective film 364 is formed and the surface is flattened, whereby the magnetic recording medium 360 is manufactured.

  As described above, according to the present embodiment, after imprinting using an imprint master having a pattern of one sector is repeated in the circumferential direction to form a disc-shaped patterned media pattern, A patterned media master can be produced by forming a sector identification pattern by making a cut in the radial direction in the linear pattern. In this case, the pattern formation time by electron beam lithography or the like can be shortened, and the production time and production cost required for producing the patterned media master can be reduced.

  Here, when the sector identification pattern having a cut line is used as shown in FIG. 17C, the electron beam draws a straight line at a predetermined angle as shown in FIG. 17B. As a result, it is possible to greatly reduce the requirement for positional accuracy during drawing. When forming the pattern for sector identification independently by electron beam drawing without forming the circumferential pattern, extremely high drawing position accuracy is required to draw with the other pattern and radial position aligned. Become. In the method described in FIG. 17, since the radial line is formed in advance and the electron beam exposure may be performed linearly in the radial direction, high pattern formation accuracy can be easily obtained.

  Various patterns for sector identification are conceivable. If 256 types are identified, there are at least 8 breaks, that is, they can be identified with an 8-bit pattern, but the number of bits in the identification signal can be increased by increasing the number of breaks and error correction functions as necessary It can also be a pattern with

  According to this example, the quality of the servo signal can be improved. In the conventional method, a disk-shaped sample coated with a resist on the silicon surface is placed on a pedestal on a stage that can rotate and uniaxially translate, and the pedestal is moved in parallel at a constant speed while rotating at a constant rotational speed. When the electron beam irradiation position on the sample surface comes to the electron beam irradiation position, the electron beam is irradiated. Thereafter, by developing the sample, a pattern can be formed in a substantially concentric pattern on the disk. On top of that, for example, a nickel layer is formed by sputtering a nickel layer, plating a nickel layer, bonding to a support plate, peeling off the resist pattern, and removing the resist residue. A master can be produced. By performing an imprint process using this father master, a mother master with inverted irregularities can be created, and by using imprint, a large number of media masters can be duplicated for each.

Here, the time required to form the pattern on the entire surface of the disk includes the area of the pattern formation area, the area of the positioning unit (hereinafter referred to as a pixel) for irradiating the electron beam, the electron beam current density, It is almost determined by the resist sensitivity. If a pixel is a square having a length of L, the area of the pixel is L ² , and therefore the number of pixels increases in inverse proportion to the square of L as L becomes finer. For example, assuming that the resist sensitivity is 30 μC / cm ² , the length of one side of a square pixel is 30 nm, the current density is 1000 A / cm ² , and the area to be patterned is 5 cm in diameter, the area is about 78.5 cm ² . The number is 8.7 × 10 ¹² pieces. Since the irradiation time of the electron beam per pixel is 30 ns, the irradiation time requires at least about 72 hours. When the length of one side of a pixel is 20 nm, this time is twice or more.

  Usually, even if the sputtering time and the plating time are added, it takes several hours at most. Therefore, most of the time in the above process is the electron beam drawing time.

  The electron beam drawing apparatus is composed of many elements such as a lens power supply, an electron gun, amplifiers, a stage system, etc., and high stability is required for all of these in long-time drawing of 72 hours according to the conventional method. This leads not only to deterioration in accuracy but also to increasing the probability of occurrence of defects such as pattern errors. In particular, when the pattern is miniaturized, it is required to improve the drawing accuracy. On the other hand, since the drawing time increases, the difficulty increases.

  On the other hand, according to the method described in this embodiment, the pattern drawing of the master disk by the electron beam takes a much shorter time, and thus the stability requirement of the electron beam writing apparatus can be greatly reduced. Conversely, extremely high stability can be obtained with the same apparatus. In particular, since the servo portion only draws a pattern orthogonal to that obtained by the common pattern, the accuracy requirement in the radial direction can be greatly reduced, and the pattern formation accuracy of the track portion can be greatly increased.

  As described above, in accordance with this example, the method using electron beam lithography for the formation of the sector identification signal is particularly effective in improving the tracking reliability. In the case where a patterned medium is used as a future high density HDD (Hard Disk Drive) medium, the effect of the present invention is expected to increase particularly at a track pitch smaller than 100 nm.

  In this example, the hard mask is etched after the resist pattern is formed by electron beam lithography. However, as described in the fourth embodiment, the hard mask material is formed by sputtering or the like after the resist pattern is formed. By removing the resist, it is also possible to form a hard mask pattern at a desired position. When the pattern of the sector identification portion is formed later, it is desirable to use an electron beam drawing apparatus with a high acceleration of 50 kV to 100 kV, for example. By using a high acceleration electron beam, scattering of the electron beam in the resist can be suppressed, and the shape of the pattern to be formed can be made more vertical.

  When performing imprinting, a common sector pattern can also be formed by using optical imprinting using a UV curable resin. As a method for forming an identification pattern not based on electron beam lithography, it is possible to form a sector identification pattern using sputtering of a hard mask by focused ion beam or gas assist etching. In the case of sputtering with a focused ion beam, there are problems such that re-adhesion is likely to occur and damage may occur, but there is an advantage that pattern development can be performed without development. When gas-assisted etching is used, there are problems such as gas processing and gas contamination, but there is an advantage that processing with less damage can be performed.

  Further, ion beam lithography can be used instead of the above-described sputtering by the focused ion beam. In this case, the possibility that ions may damage the substrate must be considered. Further, X-ray lithography, EUV lithography, and optical lithography can be used instead of electron beam lithography. However, in any case, a high-accuracy mask is prepared and the lithography apparatus itself is extremely large. Furthermore, there is a problem that the resolution is inferior to that of electron beam lithography. Therefore, electron beam lithography is most suitable.

  It is also possible to form the identification pattern by etching the hard mask with an ion beam using a stencil mask dedicated to the sector identification pattern. Here, on the stencil mask, a sector identification pattern is formed in each sector identification area corresponding to each sector. For this reason, since the sector identification pattern can be formed collectively for all sectors, the manufacturing time and the manufacturing cost can be reduced.

  When a stencil mask is used, there is an advantage that the process time can be drastically shortened, but there is a problem that the cost of forming the stencil mask and high-precision mask position control are required. Which method is used is determined by the specifications and applications of the magnetic recording medium, and the effect of the present invention can be obtained by any method.

  Also, imprinting can be used to form the sector identification pattern. A disc-shaped imprint master for forming an identification pattern is prepared, and using this, after forming the common sector pattern, a resist is applied again, and a sector identification pattern is formed by an imprint method.

  Further, when the time for forming one sector pattern by electron beam drawing is short enough to allow, the common sector pattern can be configured to include a plurality of sectors. For example, in the case of 512 sectors, even if one common sector pattern includes four sectors, the electron beam writing time can be reduced to 1/128. By doing so, the electron beam drawing time is extended, but the number of imprints can be reduced. It is desirable to select the optimum number of sectors in terms of shortening the entire manufacturing process.

  In the case of including a plurality of sectors, the arrangement is not only arranged side by side in the angular direction, but for example, if the total number of sectors is an even number, two are arranged at positions 180 degrees apart from each other, or 90 if the number is a multiple of 4. Various arrangements are conceivable, such as four arrangements every degree or six arrangements every 60 degrees if they are multiples of six. In this case, it becomes easy to mechanically match the center of the father mask having the common sector pattern with the center of the mother mask substrate. The number of sector patterns formed on the father master (imprint master) is not limited to 1, 2, 4 and 6, and can be changed as appropriate according to the specifications.

(Application example for LSI pattern formation)
The pattern forming methods according to the first to fourth embodiments can also be applied when forming a fine semiconductor pattern of an LSI.

  First, a description will be given of LSI pattern formation for connecting patterns formed by an imprint process or the like by applying the pattern formation method according to the fourth embodiment. In recent years, LSI patterns have been miniaturized and densified, but there are repetitions of the same pattern as in memory elements. Therefore, if a small stamper for repetitive patterns is prepared in advance and used for the imprint master manufacturing process for one LSI chip, the electron beam drawing time required for forming the imprint master is greatly reduced. I can do it.

  For example, it is assumed that a pattern in which the block 1 and the block 2 are adjacent to each other is formed on the substrate by an imprint process as shown in FIG. A block is a configuration of an electronic circuit. At this time, in order to connect the block 1 and the block 2, a hard mask pattern in which the width of the end portion of the conducting wire to be connected to each block (W in FIG. 22A) is widened is formed (see FIG. 22 (a) hatched portion). Thereafter, a resist for electron beam lithography is applied on the substrate, and an electron beam is irradiated so as to connect the conductive wires to be connected to the block 1 and the block 2 (FIG. 22B). Then, a resist pattern is formed through a development process, and a hard mask is formed by sputtering or the like. Thereafter, when the resist is removed, the block 1 and the block 2 are connected as shown in FIG.

  As described above, when the small stamper is repeatedly imprinted with respect to the repetitive pattern, the imprint master can be produced in a shorter time than the case where the entire imprint master in one LSI area is formed by electron beam drawing. . Since the hard mask can be added at a desired position after the repeated pattern is formed, the unit regions can be easily connected.

  Further, when the connection pattern of the unit region is performed by electron beam writing, very high positional accuracy is required for electron beam writing, but a hard mask pattern having a wide end portion of the conductor to be connected is formed. As a result, the accuracy requirement required for electron beam drawing can be relaxed.

  If the imprint master manufacturing method according to the first to fourth embodiments is used, the circuit can be easily changed. In some cases, a plurality of circuit blocks are formed in the entire circuit, and the operation is determined by the connection of the circuit blocks. FIG. 23 is a diagram illustrating a process for realizing a desired circuit connection. FIG. 23 shows nine blocks. Each of the nine blocks is connected by a conducting wire. In this case, an imprint master having all connections formed in advance is prepared, and the hard mask and resist are imprinted on the substrate as a father master, and the hard mask is etched using the resist as a mask. Then, a hard mask pattern is formed. This hard mask pattern is a hard mask pattern in which all assumed connections are made as shown in FIG. As described in the first embodiment, a resist for electron beam lithography is applied on the hard mask pattern, and electron beam lithography is performed on unnecessary connection portions as shown in FIG. Then, after performing the development process, the hard mask is etched using the resist pattern as a mask. Thereby, as shown in FIG. 23C, the hard mask of unnecessary connection portions is removed, and a circuit in which a desired connection is made can be obtained. When this method is used, it is possible to prepare a large number of masters at the stage shown in FIG. 23 (a) and prepare masters with corrections according to design. Needless to say, the connection between the blocks is not limited to one, but can be applied to a plurality of connections, that is, a case where a plurality of inputs / outputs are used. By applying the produced imprint master to the custom LSI manufacturing process, it is possible to reduce the cost of manufacturing the custom LSI as compared with the case of newly creating a master.

(Modification)
In addition, this invention is not limited to each Example mentioned above. It is also possible to combine the hard mask etching process and the film formation process, perform the film formation process after performing the etching process, or perform the etching process after performing the film formation process. The imprint process can use either thermal imprint UV imprint in any case. In addition, the material and thickness of the substrate, the imprint film to be formed thereon, and the hard mask and conductive film formed by sputtering, plating, and the like can be appropriately changed according to the specifications.

  In addition, various modifications can be made without departing from the scope of the present invention.

30 ... Father master, 31 ... Substrate, 32 ... Resist, 33 ... Ni film, 34 ... Ni film, 40 ... Imprint master, 41 ... Conductor substrate, 42 ... Hard mask, 43 ... Resist, 44 ... Resist, 45 ... Ni film, 50 ... imprint master, 51 ... insulator substrate, 52 ... conductive film, 53 ... resist, 54 ... antistatic film, 60 ... imprint master, 150 ... magnetic recording / reproducing device, 154 ... suspension, 155 ... actuator Arm, 156 ... Voice coil motor, 157 ... Bearing unit, 160 ... Spindle motor, 180 ... Recording medium disk, 200 ... Sector, 210 ... Servo data area, 211 ... Preamble pattern, 212 ... Sector identification pattern, 213 ... Track information Pattern, 214 ... burst pattern, 220 ... recording data area, 230 Imprint father master for common sector, 236 ... Common sector pattern, 237 ... Mark, 241 ... Pattern for pattern production, 290 ... Mark, 301: Mother master, 341 ... Substrate, 342 ... Material film, 343 ... Ni film, 344 ... Ni film, 350 ... Master disk (stamper) of patterned media, 360 ... Magnetic recording medium, 361 ... Substrate, 362 ... Magnetic film, 363 ... Resist, 364 ... Protective film

Claims (10)

Forming a hard mask on the substrate;
Applying a first resist on the hard mask and forming a first resist pattern on the first resist such that a portion of the upper surface of the hard mask is exposed;
Etching the exposed hard mask using the first resist pattern as a mask until the substrate surface is exposed, and forming a first hard mask pattern on the hard mask;
Removing the first resist;
Applying a second resist on the hard mask and the substrate, and drawing the second resist on a region where the hard mask exists with an electron beam;
Forming a second resist pattern on the second resist by etching the second resist at a position where the electron beam is drawn so that the hard mask is exposed;
Etching the exposed hard mask using the second resist pattern as a mask, and forming a second hard mask pattern on the hard mask. Forming a first hard mask on the substrate;
Applying a first resist on the first hard mask and forming a first resist pattern on the first resist such that a part of the upper surface of the first hard mask is exposed;
Etching the exposed first hard mask with the first resist pattern as a mask until the substrate surface is exposed, and forming a first hard mask pattern on the first hard mask;
Removing the first resist;
Applying a second resist on the first hard mask and the substrate, and drawing the second resist on the region of the substrate with an electron beam;
Forming a second resist pattern on the second resist by etching the second resist at a position where the electron beam is drawn so that the substrate is exposed;
Forming a second hard mask on the second resist pattern and on the substrate, removing the second resist, and forming a second hard mask pattern. Forming method. The substrate is a substrate made of an insulating material,
3. The pattern forming method according to claim 1, wherein, in the step of drawing with the electron beam, drawing of the electron beam is performed after a conductive film is further formed on the second resist. Forming a conductive film on the substrate;
Forming a hard mask on the conductive film;
Applying a first resist on the hard mask and forming a first resist pattern on the first resist such that a portion of the upper surface of the hard mask is exposed;
Etching the exposed hard mask with the first resist pattern as a mask until the surface of the conductive film is exposed, and forming a first hard mask pattern on the hard mask;
Removing the first resist;
Applying a second resist on the hard mask and the conductive film, and drawing the second resist on a region where the hard mask exists with an electron beam;
Forming a second resist pattern on the second resist by etching the second resist at a position where the electron beam is drawn so that the hard mask is exposed;
Etching the exposed hard mask using the second resist pattern as a mask, and forming a second hard mask pattern on the hard mask. Forming a conductive film on the substrate;
Forming a first hard mask on the conductive film;
Applying a first resist on the first hard mask and forming a first resist pattern on the first resist such that a part of the upper surface of the first hard mask is exposed;
Etching the exposed first hard mask with the first resist pattern as a mask until the surface of the conductive film is exposed, and forming a first hard mask pattern on the first hard mask;
Removing the first resist;
Applying a second resist on the first hard mask and the conductive film, and drawing the second resist on a region where the conductive film exists with an electron beam;
Forming a second resist pattern on the second resist by etching the second resist at a position where the electron beam is drawn so that the conductive film is exposed;
Forming a second hard mask on the second resist pattern and the conductive film, removing the second resist, and forming a second hard mask pattern. Pattern forming method.   The pattern forming method according to claim 1, further comprising a step of etching the substrate using the second hard mask pattern as a mask. The pattern forming method according to any one of claims 1 to 5, wherein a pattern of a disk-shaped patterned media master is formed.
The step of forming the first resist pattern imprints a master including a pattern for recording data of the patterned media master and a linear pattern common to each sector identification pattern of the patterned media master. Forming a first resist pattern and drawing the electron beam, wherein the electron beam is drawn in a radial direction of the patterned media master according to the sector identification pattern. Method.   A plurality of the linear patterns are spaced apart in the radial direction and arranged in parallel. In the step of drawing the electron beam, the same circumferential direction position of each linear pattern of the same sector is obtained by scanning the electron beam in the radial direction. 8. The pattern forming method according to claim 7, wherein a cut is made in the upper resist pattern. Forming a stamper by imprinting using a patterned media master produced by the method according to claim 7 or 8,
Forming a magnetic layer on the support substrate, and forming a pattern on the resist by imprinting using the stamper on the substrate on which the resist is formed on the magnetic layer;
Forming a magnetic pattern by selectively etching the magnetic layer using the pattern formed on the resist as a mask;
A method for manufacturing a magnetic recording medium, comprising:   A method of manufacturing an LSI, comprising: a step of forming a stamper by imprinting using an imprinting master manufactured by the method according to claim 1; and a lithography step using the stamper.

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