JP2012094781A - Electron beam exposure device, electron beam exposure method, original plate and method for producing the same, and working mold and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress occurrence of error attributable to the resolution of a detector.SOLUTION: A device includes: resolution input means for inputting a resolution of a detector separately used for detecting information of a data region and a servo signal of a servo region on a magnetic recording medium; exposure position candidate determination means for determining a candidate α, β of exposure positions by setting, on a substrate 4, a distance multiplied by a natural number of the resolution input by the resolution input means, the distance between a candidate α, β of a certain exposure position and a candidate α, β of another exposure position; movement means for moving an irradiation position of an electron beam relatively to the substrate 4; and exposure means for optically exposing with a form corresponding to a servo pattern and to a data pattern. Further, the exposure is performed only on a candidate of a certain exposure position determined by the exposure position candidate determination means by using the exposure means while the substrate 4 is moved by the movement means, and/or the exposure is performed continuously from the candidate α, β of a certain exposure position as starting point and the candidate α, β of another exposure position as ending point.

Description

  The present invention relates to an electron beam exposure apparatus, an electron beam exposure method, a master and its manufacturing method, and a working mold and its manufacturing method.

  A patterned media type magnetic recording medium is known as one of media used in a magnetic recording / reproducing apparatus (hereinafter referred to as a magnetic recording apparatus) such as a hard disk drive.

  In recent years, an “imprint method” has been used as a method for forming a pattern in this magnetic recording medium. In the imprint method, an uneven pattern is formed on an original mold called a stamper, and an inverted pattern obtained by inverting the unevenness of the uneven pattern is formed on a magnetic recording medium or another working mold by transfer from the stamper. It is a technique to do. In that case, it is common to form a concavo-convex pattern on the mold as the original mold using a photolithography method.

  In the photolithography method, a resist pattern is formed by sequentially performing “resist film formation”, “resist film exposure”, and “resist film development” on a substrate to be a mold base (material). Among these, an electron beam drawing apparatus is used for exposure of the resist film. The electron beam lithography apparatus is an apparatus that exposes a resist film by irradiating an electron beam onto a resist film formed on a substrate.

  As described above, after the exposure of the predetermined pattern shape (ie, pattern drawing) is completed by irradiating the resist film with the electron beam, the resist film exposed by the pattern drawing is developed to form a resist pattern on the substrate. . Furthermore, the resist pattern is used as a mask to etch the substrate, thereby obtaining a mold in which the above pattern is formed.

A magnetic recording medium can be produced by using the mold thus formed (so-called “master” or “master mold”), or a working mold is produced from this master and a magnetic recording medium is produced by this working mold. You can also
The “working mold” referred to here is a replica in which irregularities are formed by transferring the irregularities of the master by imprinting and inverting the irregularities once or a plurality of times. In addition, the working mold in this specification mainly refers to a mold that transfers a pattern to a magnetic recording medium that is a final product, among the replicas. Of course, this working mold also includes a mold for producing a mold for transferring a pattern to a magnetic recording medium as a final product.

  As a technique for manufacturing a magnetic recording medium using an imprint mold structure, a technique described in Patent Document 1 is known. Specifically, the data address mark is normally written by a magnetic head, and a technique is formed in which a concavo-convex pattern corresponding to the data address mark is formed in the groove portion of the imprint mold structure. With this configuration, in the magnetic recording medium formed by imprinting, it is possible to avoid reading failure and misalignment during writing due to thermal fluctuations and defects.

It is also known to manufacture a magnetic recording medium having a bit-like pattern from an imprint stamper (see, for example, Patent Document 2). In Patent Document 2, in a magnetic recording medium, a minute position detection unit is configured by a different number of magnetic dots in the circumferential direction around a center line where magnetic dots in a data area are arranged to suppress magnetization reversal. Describes a technique for maintaining a stable servo pattern.

JP 2009-245534 A JP 2010-40099 A

  In recent years, the pattern size of the patterned media has been increasingly miniaturized. This miniaturization is performed in a nano size, and the miniaturization is approaching to the resolution level of a magnetic recording medium inspection apparatus and a magnetic recording apparatus that performs reading and writing.

As an example of this resolution, when an apparatus having a master clock of 500 MHz is used, the resolution when the relative linear velocity between the electron beam and the substrate used in the inspection apparatus or magnetic recording apparatus is 1 m / s is 2 nm. On the other hand, the recent pattern size is a line and space pattern, and a fine pattern of a level of 25 nm (line: space = 1: 1) is being realized.
In this specification, “resolution” means inspection when the relative linear velocity of an energy beam (including a light beam, an electron beam, etc.) used in an inspection apparatus or a magnetic recording apparatus is 1 m / s. It is the reciprocal of the master clock of the device or magnetic recording device.

Thus, it has been discovered by the present inventors that a problem occurs when the order of resolution and pattern size is close.
This defect will be specifically described with reference to FIG. 1 in the case where a bit-like pattern (hereinafter also simply referred to as a bit) is formed.

  As shown in FIG. 1A, it is assumed that, for example, bit-shaped convex portions (magnetic portions) are formed on a magnetic recording medium as designed. If the pattern is formed as designed, no error should occur.

  However, in the magnetic recording apparatus, only the part corresponding to the resolution can be read and written. That is, as shown in FIG. 1B, reading and writing can be performed only in the broken line portions arranged at the resolution of 2 nm.

On the other hand, even if the pattern is formed as designed as described above, the center point (x) of the bit does not exist in the broken line portion shown in FIG.
If the center point of the bit does not exist in the broken line portion shown in FIG.

In other words, when reading / writing the magnetic recording medium, there is a possibility that the position of the bit may be shifted and recognized due to the resolution limit of the magnetic recording apparatus. Specifically, even if the center point of the bit A exists in a readable / writable part (that is, the broken line part in FIG. 1B), the center point of the bit B adjacent thereto is shown in FIG. The case where it does not exist in the broken line part to show comes out.
In this case, a phenomenon occurs in which reading / writing is performed not in the portion a originally intended to be read / written but in the adjacent broken line portion b separated according to the resolution.

Suppose the master clock is 500 MHz and the relative linear velocity is 1 m / s (ie, the resolution is 2 nm).
In this case, when the position of a pattern (a synchronization signal detection unit 212b described later) that starts reading / writing recognition in the magnetic recording device is set to x = 0 nm, the magnetic recording device has only points of x = 2 nm, 4 nm, 6 nm,. Unable to recognize reading and writing.
For example, the bit A at a point where x = 4 nm can be read and written without any problem. However, when the center of the bit B exists at a point where x = 11 nm, reading / writing is not performed in the first place, or reading / writing is performed at a point where x = 10 nm or 12 nm. If reading / writing is not performed, an error will occur in the first place. Even if reading / writing can be performed at a point where x = 10 nm as shown in FIG. Will occur.

  As described above, even though the pattern is formed in an analog manner, data is rounded and a quantization error is generated by performing digital recognition at the read / write and inspection stages. As a result, positional deviation occurs. Hereinafter, this positional shift is also referred to as “data fall” or simply “fall”.

  In the case of a magnetic recording medium using a bit-like pattern, it is considered that about 10% of the bit diameter is an allowable range in positional deviation such as reading and writing. Currently, in exposure with an electron beam, the bit diameter is about 12.5 nm. As a result, only a deviation of about 1.25 nm is allowed. Nevertheless, as shown in FIG. 1B illustrated earlier, when the data is shifted in the direction away from each other between the adjacent bits B and C, a shift of at least 2 nm in total occurs. The probability of occurrence of errors during reading and writing is significantly increased.

  This defect not only causes a read / write error of the magnetic recording medium, but may cause a serious situation from the mold manufacturing process for manufacturing the master disk or the working mold to the shipping process. For example, even if a master or working mold having a pattern as designed can be produced, first, there is a possibility that the above-described error may occur due to the resolution of the pattern inspection apparatus. In addition, an error may occur at the final stage until the magnetic recording medium is manufactured as described above. In the first place, despite the fact that a fine pattern was formed as designed, an error occurs at the subsequent stage of the magnetic recording medium. Much time and effort must be spent, and in some cases, all processes, including the underlying mold, may need to be reviewed and even remanufactured.

  SUMMARY OF THE INVENTION The main object of the present invention is to provide an electron beam exposure apparatus, an electron beam exposure method, a master and its manufacturing method, a working mold and its manufacturing method that suppress the occurrence of errors due to the resolution of the detector.

  As described above, the present inventors have obtained the knowledge that “data transition” has a significant influence on the entire manufacturing process of a magnetic recording medium due to the proximity of the order of resolution and pattern size. Based on this knowledge, the present inventors first examined a means for increasing the master clock of the inspection apparatus or magnetic recording apparatus (that is, improving the resolution (eg, resolution: 2 nm → 1 nm)).

However, the master clock of the inspection device or the magnetic recording device is finite, and the inspection device or magnetic recording device having a higher master clock is remarkably expensive. In addition, there is a situation where a low-cost circuit design is required for a hard disk circuit on which a magnetic recording medium is mounted. If an expensive apparatus is used against this situation, the price is added to the magnetic recording medium itself. For this reason, the above-described means is difficult in terms of cost.
In addition, although the means of making a relative linear velocity slow is also considered, if it sets in such a way, much time will be required for master production in the first place. If so, the work efficiency may be reduced.

Therefore, the present inventors have obtained the knowledge that the resolution of an inspection apparatus or a magnetic recording apparatus used for a magnetic recording medium to be manufactured later is taken into consideration in advance from the production stage of the master. More specifically, the following findings were obtained. That is, first, a place where digital pattern recognition can be performed (hereinafter referred to as “exposure position candidate”) is set on the base substrate of the master according to the resolution of the apparatus used later. Keep it. Based on the idea that there is a candidate for the exposure position, this is the knowledge that the substrate is exposed and patterned.
Design the pattern shape first as before, and form the pattern on the master in an analog fashion,
Thereafter, this knowledge is completely different from a technique for performing digital inspection and recording on a magnetic recording medium to be manufactured.

  Specifically, the distance from one exposure position candidate to another exposure position candidate at a predetermined position in each track on the substrate on which the master is based is determined by an inspection apparatus or magnetic recording apparatus to be used later. Set to a natural number multiple of the resolution. Then, in order to suppress the occurrence of data transition, exposure is performed only on the exposure position candidates determined in this way, and / or one exposure position candidate is a start point and another exposure position candidate is an end point. Continuous exposure is performed. In this way, a means has been conceived in which the master is prepared from the beginning so that the pattern is always arranged at the broken line as shown in FIGS. The present inventors have found that it is possible to guarantee at this stage of master production that the occurrence of errors due to the resolution of the apparatus used after production of the master is suppressed by this means.

The embodiment of the present invention based on this finding is as follows.
The first aspect of the present invention is:
In an electron beam exposure apparatus for producing a master used for producing a magnetic recording medium having a plurality of tracks or a working mold used for producing the same by imprinting,
Moving means for moving the irradiation position of the electron beam on the main surface of the substrate relative to the substrate while holding the substrate on which the photosensitive film is formed on one main surface;
By irradiating the data portion and servo portion set on the substrate with an electron beam, exposure of a shape corresponding to a data pattern serving as a basis of a data region for recording information on a magnetic recording medium is performed. The servo section on the substrate is exposed to the data section on the substrate and exposed in a shape corresponding to the servo pattern serving as the basis of the servo area for specifying the track position and / or pattern position of the data area on the magnetic recording medium. Exposure means to perform,
On the magnetic recording medium, resolution input means for inputting resolution of a detector separately used for detecting information in the data area and servo signals in the servo area;
The resolution input means inputs the distance from one exposure position candidate to another exposure position candidate in at least the servo section, the servo section to the data section, and the data section in each track on the substrate. Exposure position candidate determination means for determining exposure position candidates on the substrate by setting the natural number times the resolution that has been performed,
With
While moving the substrate by the moving means, the exposure means is used to perform exposure only on a certain exposure position candidate determined by the exposure position candidate determining means, and / or a certain exposure position candidate The electron beam exposure apparatus is characterized in that the exposure is continuously performed with a starting point as a starting point and another exposure position candidate as an end point.
However, the data pattern includes a pattern serving as a basis of the data pattern in addition to the data pattern itself.
A second aspect of the present invention is the aspect described in the first aspect,
When the magnetic recording medium has a plurality of concentric tracks,
Track pitch input means for inputting the distance between the tracks;
A rotating means for rotating the substrate while holding the substrate on which the photosensitive film is formed on one main surface;
Rotation control means for controlling the drive of the rotation means;
Further comprising
In each track, at least the data pattern form of the data portion is separated in the radial direction and the circumferential direction for each bit,
By transmitting the distance (TP) between the tracks from the track pitch input means to the exposure position candidate determination means, a shift in the bit period (ΔBP) associated with the increase in the track diameter is obtained. The exposure position candidate determination means sets exposure position candidates so that ΔBP between the track (T ₀ ) and the track (T ₁ ) adjacent to the track in the outer circumferential direction is a natural number multiple of the resolution. It is characterized by determining.
However, ΔBP = BP ₀ * TP / r
r: radius of track T ₀ BP ₀ : bit period of track T ₀
A third aspect of the present invention is the aspect described in the first or second aspect,
The exposure by the exposure means is performed with a bit having a circular shape in plan view.
A fourth aspect of the present invention is the aspect according to any one of the first to third aspects,
The exposure position candidate determination means is a natural number multiple of the resolution input by the resolution input means for the distance from one exposure position candidate to another exposure position candidate in the entire track on the substrate. In this case, exposure position candidates are determined on the substrate.
A fifth aspect of the present invention is the aspect according to any one of the first to fourth aspects,
The electron beam irradiation by the exposure unit is performed at a constant linear velocity by the moving unit.
A sixth aspect of the present invention is the aspect according to any one of the first to fifth aspects,
An electron beam polarizing means for polarizing the electron beam emitted from the exposure means;
The electron beam polarization means performs exposure with an electron beam on the exposure position determined by the exposure position candidate determination means.
The seventh aspect of the present invention is
In an electron beam exposure method for manufacturing a master used for manufacturing a magnetic recording medium having a plurality of tracks or a working mold used for manufacturing the same by imprinting,
A moving step of moving the irradiation position of the electron beam on the main surface of the substrate relative to the substrate while holding the substrate on which the photosensitive film is formed on one main surface;
By irradiating the data portion and servo portion set on the substrate with an electron beam, exposure of a shape corresponding to a data pattern serving as a basis of a data region for recording information on a magnetic recording medium is performed. The servo section on the substrate is exposed to the data section on the substrate and exposed in a shape corresponding to the servo pattern serving as the basis of the servo area for specifying the track position and / or pattern position of the data area on the magnetic recording medium. An exposure process to be performed,
On the magnetic recording medium, a resolution input step of inputting a resolution of a detector separately used for detecting information in the data area and a servo signal in the servo area;
The distance from one exposure position candidate to another exposure position candidate is input by the resolution input step in at least the servo section, the servo section to the data section, and the data section in each track on the substrate. Exposure position candidate determination step for determining exposure position candidates on the substrate by setting the natural number times the resolution that has been performed,
Have
While moving the substrate in the moving step, in the exposure step, exposure is performed only to a certain exposure position candidate determined in the exposure position candidate determination step, and / or a certain exposure position candidate is a starting point. In addition, the electron beam exposure method is characterized in that the exposure is continuously performed with another exposure position candidate as an end point.
However, the data pattern includes a pattern serving as a basis of the data pattern in addition to the data pattern itself.
The eighth aspect of the present invention is
In a master used when imprinting a magnetic recording medium having a data portion and a servo portion formed on a substrate and having a plurality of tracks or a working mold used for producing the magnetic recording medium,
The data portion is a portion where a data pattern serving as a base of a data area for recording information on a magnetic recording medium is formed,
The servo part is a part in which a servo pattern serving as a basis of a servo area for specifying a track position and / or a pattern position of a data area in a magnetic recording medium is formed,
The distance from one exposure position candidate to another exposure position candidate is a natural number multiple of the detector resolution within at least the servo section, the servo section to the data section, and the data section in each track on the substrate. Servo patterns and only the exposure position candidates set to be and / or continuously with the set exposure position candidate as the start point and the set another exposure position candidate as the end point. The master is characterized in that a data pattern is formed.
However, the data pattern includes a pattern serving as a basis of the data pattern in addition to the data pattern itself. The detector is a detector that is used during or after manufacture of the magnetic recording medium and detects a servo signal in the servo area and information in the data area of the magnetic recording medium.
A ninth aspect of the present invention is the aspect described in the eighth aspect,
A plurality of tracks are formed concentrically, and in each track, at least the data pattern form of the data portion is separated in the radial direction and the circumferential direction for each bit,
ΔBP between a certain track (T ₀ ) and a track (T ₁ ) adjacent to the outer periphery from the track is a natural number times the resolution.
However, ΔBP = BP ₀ * TP / r
DerutaBP: deviation of bit periods associated with the diameter of the track is enlarged r: radius BP ₀ tracks _{T 0:} bit period of the track _{T 0} TP: the distance between the tracks _{T 0} and _{T 1.}
A tenth aspect of the present invention is the aspect described in the eighth or ninth aspect,
The data pattern is formed by bits having a circular shape in a plan view.
An eleventh aspect of the present invention is the aspect according to any one of the eighth to tenth aspects,
A plurality of tracks are formed concentrically, and at least the form of the data pattern is separated in the radial direction and the circumferential direction for each bit in each track.
A twelfth aspect of the present invention is the aspect according to any one of the eighth to eleventh aspects,
The exposure position candidates are set so that the distance from one exposure position candidate to another exposure position candidate is a natural number multiple of the resolution of the detector in the entire track on the substrate. It is characterized by that.
A thirteenth aspect of the present invention is a working mold characterized by being manufactured by imprinting from the master according to any one of the eighth to twelfth aspects.
The fourteenth aspect of the present invention provides
A master disk used when imprinting a magnetic recording medium having a plurality of tracks or a working mold used for manufacturing the magnetic recording medium, and having a data part and a servo part on a substrate. ,
The data portion is a portion where a data pattern serving as a base of a data area for recording information on a magnetic recording medium is formed,
The servo part is a part in which a servo pattern serving as a basis of a servo area for specifying a track position and / or a pattern position of a data area in a magnetic recording medium is formed,
The distance from one exposure position candidate to another exposure position candidate is a natural number of the resolution of the detector in at least the servo section, the servo section to the data section, and the data section in each track on the substrate. Servo pattern continuously only for exposure position candidates set to be doubled and / or with the set exposure position candidate as a starting point and the set another exposure position candidate as an end point And a master pattern manufacturing method characterized by forming a data pattern.
However, the data pattern includes a pattern serving as a basis of the data pattern in addition to the data pattern itself. The detector is a detector that is used during or after manufacture of the magnetic recording medium and detects a servo signal in the servo area and information in the data area of the magnetic recording medium.
A fifteenth aspect of the present invention is a working mold manufacturing method, wherein a working mold is manufactured by imprinting from a master disk manufactured by the manufacturing method according to the fourteenth aspect.

  According to the present invention, it is possible to suppress the occurrence of errors due to the resolution of the detector.

It is the schematic which shows the mode of the data fall in this embodiment. (A) is a figure which shows the bit-shaped pattern formed on the board | substrate as designed, and cross mark (x) is a bit center. (B) is a figure which shows the bit-like pattern at the time of putting the division | segmentation (broken line) for every resolution | decomposability of a detector, and a white circle ((circle)) is a part by which a bit should be detected by a detector by design by design It is. (C) is a diagram showing positions (black circles (●)) at which bits are actually detected by the detector after inserting a delimiter (broken line) for each resolution of the detector. It is a figure which shows an example of the structure of the board | substrate used as the object of exposure. It is a figure which shows the board | substrate in this embodiment, and is a figure which shows the data part and servo part in that board | substrate, and a data pattern. FIG. 5 is a schematic diagram for explaining a bit period shift (ΔBP) when a plurality of concentric tracks are formed. A broken line is a break for each resolution of the detector. A white circle (◯) is a portion where a bit is detected by the detector. It is the schematic which shows the structural example of the electron beam exposure apparatus which concerns on embodiment of this invention. It is a figure which shows the mode at the time of electron beam exposure. It is the schematic which shows a mode that the candidate of the exposure position in this embodiment is determined on a board | substrate. It is the schematic which shows the various exposure shapes in a modification.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
In the present embodiment, description will be given in the following order.
1. Structure of master (substrate) a) Servo part on master b) Data part on master c) Pattern arrangement conditions (selection conditions for exposure position candidates)
2. Basic configuration of electron beam exposure system (mechanism system configuration, control system configuration)
3. 3. Basic operation of electron beam exposure apparatus Control method of electron beam exposure apparatus (including electron beam exposure method)
5). Effects of the embodiment 6. Modified example

<1. Master (substrate) structure>
FIG. 2 shows an example of the structure of the substrate 4 to be exposed, in which (A) is a plan view and (B) is a side sectional view.

  In the present embodiment, the substrate 4 is a master used to manufacture a magnetic recording medium having a plurality of tracks, or to manufacture a working mold used for manufacturing a magnetic recording medium having a plurality of tracks by imprinting. It is a substrate. Speaking of the material, in the present embodiment, the quartz glass substrate is used. The planar shape of the substrate 4 is circular (that is, a disk shape). A resist film 18 as an example of a photosensitive film is formed on one main surface (upper surface) of the substrate 4. In the present embodiment, the resist film 18 uses a positive resist.

  When a positive resist is used, a portion exposed by electron beam irradiation is removed by subsequent development processing. Since the positive resist has higher sensitivity to the electron beam and higher resolution as compared with the negative resist, it is preferable to form (deposit) the resist film 18 using the positive resist. In the present embodiment, it is assumed that the resist film 18 is formed using a positive resist.

  In the substrate 4, almost the entire region (deposition region) where the resist film 18 is formed may be the subject of exposure, or a part of the region may be subject to exposure. Here, as an example, a region outside the circular region E0 is defined as a resist film except for a circular region E0 from the physical center Cp of the substrate 4 to the length Lr1 in the radial direction of the substrate 4 therefrom. Eighteen effective areas (exposure target areas) 19 are set.

  The effective area 19 of the resist film 18 described here refers to an area where a resist pattern is formed by a phenomenon process performed after electron beam exposure. For this reason, the effective area of the resist film 18 is, for example, when a disk-shaped recording medium is manufactured using a disk master based on a pattern obtained by electron beam exposure and subsequent development processing. This area corresponds to the area transferred to the surface (area necessary for maintaining the quality of the product).

In the effective area 19, as shown in FIG. 3, a data portion 21 and a servo portion 22 adjacent to the data portion 21 are formed. The servo unit 22 and the data unit 21 are alternately arranged in each concentric track.
The data portion 21 is a portion on which a data pattern 21 ′ serving as a basis of a data area for recording information on a magnetic recording medium is formed.
The servo section 22 is a portion where a servo pattern 22 'serving as a basis of a servo area for specifying a track position and / or a pattern position on a magnetic recording medium is formed.
In the present embodiment, a case will be described in which both the data pattern 21 ′ and the servo pattern 22 ′ are formed with unevenness.

It should be noted that hereinafter, what is provided on the master or working mold with respect to the portion where the pattern exists uses the word “part”, for example, “data part” and “servo part”.
On the other hand, the word “area” is used for a portion where a pattern in a magnetic recording medium to be formed in the future by this master or working mold is used, for example, “data area” and “servo area”.
In short, the concave / convex pattern of the data portion 21 and the servo portion 22 provided on the master disk of the present embodiment is transferred to a magnetic recording medium by imprinting to become a data area and a servo area in the magnetic recording medium. .

  Hereinafter, the data part 21 and the servo part 22 in the master will be described in the order of the servo part 22 → the data part 21. In this case, a case where a plurality of tracks are formed concentrically as shown in FIG. 3 due to the circular substrate is described.

The data pattern 21 ′ in the data section 21 and the servo pattern 22 ′ in the servo section 22 described below are formed as “exposure position candidates (also referred to as pattern position candidates)” on the substrate 4 as described above. Will be. Based on this, in the following description, the functions of the servo unit 22 and the data unit 21 will be described first. Thereafter, “exposure position candidates” will be described in detail.
Hereinafter, the data pattern 21 ′ and the servo pattern 22 ′ are also simply referred to as “pattern” for convenience of explanation.

a) Servo part on master disk In the circumferential direction in each concentric track, in the servo part 22, a preamble part 221, an address part 222, and a burst part 223 are configured in this arrangement order.

(Preamble part)
The preamble portion 221 is a portion where information for synchronizing the clock of the reproduction signal is recorded on the magnetic recording medium. The preamble unit 221 further includes a synchronization signal generation unit 221a and a synchronization signal detection unit 221b.

The synchronization signal generation unit 221a functions to adjust the amplification factor of the signal amplifier to make the amplitude constant before calling the servo information, and to generate the sampling timing of the A / D conversion (Analog to Digital Converter) clock signal. Have The synchronization signal generation unit 221a is continuously formed in the radial direction in the entire or partial range from the inner periphery to the outer periphery of the medium. And it forms at a constant interval in the circumferential direction.

  Next, the synchronization signal detection unit 221b is a characteristic pattern indicating the start of servo information. The synchronization signal detection unit 221b is continuously formed in the radial direction in the entire or partial range from the inner periphery to the outer periphery of the master. And it has a part with a long bit length in the circumferential direction compared with the synchronizing signal generation part 221a. This part finally becomes a single magnetic part or a plurality of magnetic parts for generating a predetermined code of several bits in the magnetic recording medium.

  The synchronization signal generation unit 221a and the synchronization signal detection unit 221b described above are parts that are one feature in the master disk of the present embodiment. The synchronization signal generation unit 221a finally becomes a magnetic unit in the magnetic recording medium, and generates a “clock” (that is, a predetermined cycle of the formed pattern) that becomes the synchronization signal. Further, the synchronization signal detection unit 221b becomes a servo pattern 22 'serving as a timing alignment reference for starting detection of the data pattern 21' in the direction from the servo unit 22 to the data unit 21 of each track.

(Address part)
The address part 222 is an ID pattern indicating a track number and a sector number for each servo frame. In the magnetic recording apparatus, the track position where the magnetic head is located is shown.

The address part 222 is continuously formed in the radial direction in the circumferential position indicating the sector number in the entire or partial range from the inner circumference to the outer circumference of the medium.
In the magnetic recording medium to which the address portion 222 of the master is transferred, the circumferential position indicating the upper digit of the track number corresponds to the address portion 222 in the entire or partial range from the inner periphery to the outer periphery of the medium. The pattern is continuous in the radial direction. On the other hand, a magnetic material that is intermittent in the radial direction of the medium is formed at the circumferential position indicating the lower digit of the track number.

(Burst part)
The burst portion 223 is a portion on the substrate corresponding to an off-track detection area in the magnetic recording medium for detecting the off-track amount from the on-track state of the cylinder address.

  When the burst portion 223 is transferred to the magnetic recording medium, information on the deviation of the position of the magnetic head from the track center is detected in the magnetic recording device by this area. A region corresponding to the burst portion 223 in the magnetic recording medium has a magnetic pattern having a specific shape and arrangement in the circumferential direction, and each magnetic pattern is arranged at equal intervals for each track in the radial direction of the medium. Has been.

  The order of arrangement in the circumferential direction within each concentric track is not limited to this order. However, as described above, the synchronization signal is generated and controlled by the preamble section 221 in the magnetic recording medium, the track position where the magnetic head is located in the magnetic recording apparatus is recognized by the address section 222, and the magnetic head is detected by the burst section 223. This order is preferable because it plays a role of recording deviation information from the track center.

b) Data part on master In this embodiment, a data part 21 is formed so as to be adjacent to the servo part 22. More specifically, the data portion 21 is formed after the burst portion 223 in the circumferential direction. This data section 21 finally becomes an area in which user data can be written in the magnetic recording medium, and this can be performed by the magnetic head of the magnetic recording / reproducing apparatus.

  The pattern may be either a discrete pattern or a bit pattern. In this embodiment, the case of a bit pattern having a circular shape in plan view will be described.

If it is a bit pattern, there exists an advantage that it can set on the basis of the approximate center position of a bit.
In other words, if there is an approximate center of a bit at a point that can be accurately recognized by the detector, the bit can be most easily recognized at that point. As a result, regardless of the size of the bit diameter, data is set by setting the distance from one exposure position candidate to another exposure position candidate to a natural number multiple of the resolution input by the resolution input means. Falling can be suppressed.

  The “detector” mentioned here is a detector that is used during or after manufacture of the magnetic recording medium, and detects a servo signal in the servo area and information in the data area of the magnetic recording medium. is there. Examples of the detector include an inspection device and a magnetic recording / reproducing device.

In each track, at least the form of the data pattern 21 ′ of the data portion 21 is separated in the radial direction and the circumferential direction for each bit. In the final magnetic recording medium, the data area is provided with a plurality of tracks having a magnetic band in which user data can be written by a magnetic head, and a non-magnetic band in which user data cannot be written is provided between adjacent tracks. It has been. That is, the magnetic recording medium is a discrete track type recording medium in which magnetic bands are physically separated by nonmagnetic bands.

c) Pattern arrangement conditions (exposure position candidate selection conditions)
In this embodiment, taking into account the resolution of a detector that should be used after the magnetic recording medium is manufactured, a pattern is formed in advance on the substrate 4 at a position where it can be reliably detected according to the resolution. More specifically, a major feature of the master disk of the present embodiment is that the data pattern 21 ′ and the servo pattern 22 ′ (that is, “pattern”) are arranged so as to satisfy the following conditions.

[Condition 1]
A distance from one exposure position candidate to another exposure position candidate is detected by at least the servo section 22 in each track on the substrate 4, between the servo section 22 and the data section 21, and within the data section 21. The pattern is formed only on the exposure position candidates set so as to be a natural number multiple of the resolution. Here, the distance from the servo part 22 to the data part 21 is the distance from the servo pattern 22 ′ at the end of the servo part 22 to the portion of the data pattern 21 ′ of the data part 21 that is closest to the servo pattern 22 ′. means.
In the present embodiment, a case will be described in which the whole of each track on the substrate is set to be a natural number multiple of the resolution. The reason why the area from the data part 21 to the servo part 22 can be excluded is <6. Modification>.

As described above, when reading / writing from / to the magnetic recording medium, there is a risk that the position of the bit may be shifted and recognized due to the limit of the resolution of the magnetic recording apparatus. Specifically, even if the center point of bit A exists in a readable / writable part, the center point of bit B adjacent thereto does not exist in the broken line part shown in FIG.
In this case, a phenomenon occurs in which reading / writing is performed not in the portion that originally intended to be read / written, but in the adjacent broken line portion separated according to the resolution.
In other words, even though the pattern is formed in an analog manner, misalignment occurs due to digital recognition at the time of reading / writing or inspection, and so-called “data shift” may occur.

  However, as in the present embodiment, by arranging the bits in consideration of the resolution of the detector at the master stage before manufacturing the magnetic recording medium, it is possible to suppress the occurrence of data transition. For example, taking into account the use of a detector with a resolution of 3 nm that can recognize the pattern only at the points of 0 nm, 3 nm, 6 nm, 9 nm, etc., the bit center is not arranged at the point of 1 nm or 2 nm. The approximate bit center is located at points of 3 nm, 6 nm, and 9 nm.

  As will be described in detail later, the “substantially center of the bit” in the present embodiment means “a part in the bit close to the bit center to the extent that the bit is recognized at a point that should be originally recognized by the detector”. That is.

  Furthermore, the above condition 1 is useful not only for data transition in the data pattern 21 'but also for digitally recognizing the servo pattern 22'. That is, the pattern is formed so as to satisfy the condition 1 over the entire effective area 19 of the substrate 4.

More specifically, as shown in FIG. 7A which is a plan view of the substrate 4, a grid-like segmentation is performed over the entire effective area 19 of the substrate 4, and exposure position candidates (α and β And other black circles) are determined in advance on the substrate 4. When the master is formed in this manner, the servo pattern 22 ′ serving as a reference for timing adjustment for starting the detection of the data pattern 21 ′ can be detected by a detector used later. Formed in the upper position. Furthermore, all other servo patterns 22 ′ and data patterns 21 ′ are also formed at positions on the substrate 4 that can be detected by the detector. As a result, the occurrence of errors due to the resolution of the detector can be suppressed.

In addition to the above [Condition 1], the following conditions may be satisfied.
[Condition 2]
In each track on the substrate 4, a pattern is continuously formed with the set exposure position candidate as a start point and the set another exposure position candidate as an end point. In the present embodiment, the preamble part 221 and the address part 222 in the servo part 22 described above are formed on the master so as to satisfy this condition.

  By satisfying condition 2, if the pattern is formed so as to connect the start point and end point of the pattern, even if a continuous pattern is formed, it can be detected by the detector. As a result, similar to Condition 1, even if the pattern is a continuous pattern that is not a bit, the occurrence of errors due to the resolution of the detector can be suppressed.

  In the present embodiment, a pattern that satisfies either condition may be formed on the master. In addition, as shown in FIG. 3, various patterns may be formed on the substrate 4 such that each pattern satisfies one of the above two conditions.

The critical value of “natural number multiple” is also described.
As for the lower limit value, it may be a multiple that can ensure a certain distance between adjacent bits according to the bit diameter. For example, when the bit diameter is 10 nm and the resolution is 2 nm, the bit center-to-center distance is more than 5 times the resolution in order to separate the form of the data pattern 21 ′ in the radial direction and the circumferential direction for each bit. It is better to make it a natural number multiple.
Regarding the upper limit, depending on the width of the data portion 21 in one track (in the case of a concentric track, the circumference of the data portion 21), a number of bits that can record predetermined information can be formed. A multiple is sufficient.

(Other parts)
As a part other than the above, it is conceivable to provide a buffer pattern made up of substantially radial convex patterns connected in the radial direction between the data pattern 21 ′ and the servo pattern 22 ′. There is no particular limitation as long as it is not impaired, and a portion other than the above can be appropriately selected according to the purpose.

(Change in pattern period due to track change)
As described above, in a concentric track, data transfer can be finally suppressed in the magnetic recording medium by satisfying at least one of the two conditions in one track. However, when a plurality of tracks are formed concentrically, the circumferential length of the outer or inner track changes. When producing a bit-like pattern, it is very preferable to make the clock at the position substantially in the center of the bit constant in each track.

Specifically, as shown in FIG. 4, a bit period shift (ΔBP) associated with an increase in the track diameter is obtained from the distance (TP) between the tracks.
However, ΔBP = BP ₀ * TP / r
r: radius of track T ₀ BP ₀ : bit period of track T ₀

Then, a certain track (T ₀ ) and the next track (from the track toward the outer periphery)
The position of the approximate bit center is determined so that ΔBP between T ₁ and T ₁ ) is a natural number multiple of the resolution.
By doing so, even if the track position changes in the final magnetic recording medium, the detector can reliably perform reading and writing at the correct position. As a result, data transition can be suppressed in all concentric tracks.

The above is the description of the configuration of the master according to the present embodiment.
Hereinafter, an electron beam exposure apparatus used for producing the master will be described.

<2. Basic configuration of electron beam exposure system>
FIG. 5 is a schematic diagram showing a configuration example of the electron beam exposure apparatus according to the embodiment of the present invention. The electron beam exposure apparatus 1 shown in FIG. 1 roughly includes an electron beam generator 2 that generates an electron beam, an electron beam control system 3 that controls the electron beam generated by the electron beam generator 2, and an exposure target. A stage mechanism 5 that supports the substrate 4 and a stage control system 6 that controls driving of the stage mechanism 5 are provided.

  In the present embodiment, the electron beam generator 2 and the electron beam control system 3 are collectively referred to as “exposure means”. The exposure means irradiates an electron beam to expose the servo section 22 on the substrate in a shape corresponding to the servo pattern 22 'that is the basis of the servo area, and data that is the basis of the data area The exposure of the shape corresponding to the pattern 21 'is performed on the data portion 21 on the substrate.

  In addition, the stage mechanism 5 and the stage control system 6 are used as “moving means”. By this moving means, the irradiation position of the electron beam on the main surface of the substrate 4 is moved relative to the substrate 4 while holding the substrate on which the photosensitive film is formed on one main surface.

  In this embodiment, since an r-θ rotation stage is used, the stage mechanism 5 serves as both “moving means” (movable along the XYZ axes) and “rotating means” (movable along the r-θ axes). ing. Further, the stage control system 6 has a function of moving the irradiation position of the electron beam relative to the substrate 4 serving as an irradiation object. In addition to this, the stage control system 6 is a “rotation control unit” that controls the driving of the “rotation unit”.

Furthermore, the electron beam exposure apparatus according to the present embodiment has a configuration in which an interface 20 for inputting data such as desired numerical values and operation patterns is added in order to perform a desired operation with respect to the above configuration. The interface 20 includes “resolution input means” described later as one of the components. Further, the interface 20 includes “exposure position candidate determination means” which will be described later.
Hereinafter, the configuration of each unit that operates according to data input to the interface 20 will be described first.

(Electron beam generator)
The electron beam generator 2 is configured by using an electron gun 7 which is an electron beam generation source. The electron gun 7 is disposed so as to face the substrate 4 supported by the stage mechanism 5. The electron gun 7 generates an electron beam downward.
In addition, the irradiation shape at the time of irradiating the substrate 4 with the electron beam is circular in plan view in the present embodiment. That is, when a linear pattern is formed, linear exposure is performed by continuously irradiating the resist on the substrate 4 with the electron beam while rotating the substrate 4 by the stage mechanism 5. And when exposing to a circular bit shape, an electron beam is irradiated instantaneously.

(Electron beam control system)
The electron beam control system 3 includes, for example, a focusing lens 8 and a blanking electrode 9 as illustrated.
And an aperture 10, an objective lens 11, and a deflector 12.

  The focusing lens 8 suppresses the spread of the beam diameter of the electron beam emitted from the electron gun 7. The focusing lens 8 is disposed between the electron gun 7 and the blanking electrode 9 on the trajectory of the electron beam from the electron gun 7 to the substrate 4.

  The blanking electrode 9 controls the progress of the electron beam to the downstream side. The blanking electrode 9 controls the progress of the electron beam so that the aperture 10 blocks the electron beam when blanking (that is, when the blanking electrode 9 is turned on). On the other hand, when blanking is not performed (that is, when the blanking electrode 9 is turned off), the progress of the electron beam is controlled so that the electron beam passes through the opening 13 of the aperture 10. The blanking electrode 9 is disposed between the focusing lens 8 and the aperture 10 on the trajectory of the electron beam from the electron gun 7 to the substrate 4.

  The aperture 10 functions to block unnecessary electron beam components during the electron beam exposure process. The aperture 10 integrally has an opening 13 for blocking unnecessary electron beam components and allowing necessary electron beam components to pass therethrough. The aperture 10 is disposed between the blanking electrode 9 and the objective lens 11 (deflector 12) on the trajectory of the electron beam from the electron gun 7 to the substrate 4.

  The objective lens 11 narrows the beam diameter of the electron beam that has passed through the opening 13 of the aperture 10. The objective lens 11 is disposed between the aperture 10 and the stage mechanism 5 on the trajectory of the electron beam from the electron gun 7 to the substrate 4.

The deflector 12 changes the direction (traveling direction) of the electron beam that has passed through the opening 13 of the aperture 10. The deflector 12 is disposed between the aperture 10 and the stage mechanism 5 together with the objective lens 11 described above on the trajectory of the electron beam from the electron gun 7 to the substrate 4.
In the present embodiment, a portion including at least the blanking electrode 9 in the electron beam control system and related to deflecting the electron beam is an “electron beam deflecting unit”.

(Stage mechanism)
The stage mechanism 5 is configured using a rotary stage 14 and a linear motion stage 15. The rotary stage 14 and the linear motion stage 15 constitute the aforementioned r-θ stage.

The rotary stage 14 holds the substrate 4 horizontally and rotates the held substrate 4. The rotary stage 14 is configured to rotate using a drive source such as a spindle motor (not shown). The rotation stage 14 is provided as an example of a rotation unit that rotates the substrate 4 while holding the substrate 4.
In the present embodiment, the rotary stage 14 is a “rotating unit”.

  The linear motion stage 15 moves linearly in a uniaxial direction (hereinafter referred to as “horizontal direction”) parallel to the horizontal plane. The linear motion stage 15 moves in the horizontal direction integrally with the rotary stage 14 and the substrate 4 held thereon. The linear motion stage 15 is provided as an example of a moving unit that moves the substrate 4 held by the rotary stage 14 in a direction parallel to the radial direction of the substrate 4.

(Stage control system)
The stage control system 6 includes a rotary stage controller 16 that controls the rotary stage 14 and a linear motion stage controller 17 that controls the linear motion stage 15.

The rotary stage control unit 16 controls driving of the rotary stage 14. More specifically, the rotary stage control unit 16 controls the rotational speed and direction of the rotary stage 14 in addition to basic operations such as rotation and stop of the rotary stage 14, for example. The rotation speed of the rotary stage 14 described here is represented by the number of rotations per unit time (unit: rpm). The rotation stage 14 recognizes the current position (rotation phase) in the rotation direction of the rotation stage 14 using, for example, a rotation position detection sensor (not shown) included in the electron beam exposure apparatus 1.
In the present embodiment, the rotation stage control unit 16 serves as a “rotation control unit”.

  The linear motion stage control unit 17 controls driving of the linear motion stage 15. More specifically, the linear motion stage control unit 17 controls the moving speed and the moving direction of the linear motion stage 15 in addition to the basic operation of moving / stopping the linear motion stage 15, for example. The rotary stage control unit 16 recognizes the current position in the movement direction of the linear motion stage 15 using, for example, a movement position detection sensor (not shown) provided in the electron beam exposure apparatus 1.

<3. Basic operation of electron beam exposure system>
Next, the basic operation of the electron beam exposure apparatus 1 according to the embodiment of the present invention will be described.

  First, the substrate 4 is placed and fixed on the rotary stage 14. At this time, the substrate 4 is positioned so that the rotation center of the rotary stage 14 and the physical center Cp of the substrate 4 coincide. Further, the substrate 4 is horizontally disposed so that the resist film 18 faces upward (the resist film 18 faces the electron gun 7).

  Next, initialization processing (for example, processing for detecting the reference position in the rotational direction of the rotary stage 14 or processing for detecting the reference position in the moving direction of the linear motion stage 15) is performed as necessary. Etc.). Each reference position is detected using, for example, the rotational position detection sensor and the movement position detection sensor described above.

  Next, the substrate 4 held on the rotary stage 14 is placed at a predetermined initial position, and the substrate 4 is rotated by driving the rotary stage 14 there. When the rotation speed of the substrate 4 is stabilized at a predetermined speed, the electron beam exposure is started at a predetermined timing. The state at that time is shown in FIG.

  In the electron beam exposure, the electron beam emitted from the electron gun 7 is focused by the focusing lens 8, and the progress of the focused electron beam is controlled by the blanking electrode 9, so that the electron beam is applied to the opening 13 of the aperture 10. Pass through. Further, the diameter of the electron beam that has passed through the aperture 10 is reduced by the objective lens 11, and the direction of the electron beam is controlled by the deflector 12.

  As a result, the resist film 18 formed on the substrate 4 is exposed concentrically by the rotational drive of the rotary stage 14. Further, the substrate 4 is moved in the horizontal direction (fine movement) by driving the linear motion stage 15, and concentric exposure is repeated for each rotation of the substrate 4 in accordance with this movement, so that the entire effective area 19 of the resist film 18 is obtained. Are exposed. However, in the concentric exposure performed while the substrate 4 is rotated once, control is performed so as to switch on / off the irradiation of the electron beam in accordance with a desired pit pattern. This switching is performed using the blanking electrode 9.

  In this embodiment, the electron beam is exposed to the substrate 4 so that a linear pattern is formed in a part of the servo unit 22. Then, in the other part of the servo part 22 and the data part 21, an electron beam is exposed on the substrate 4 so that a pattern composed of circular bits is formed.

<4. Control method of electron beam exposure apparatus (including electron beam exposure method)>
Next, a control method of the electron beam exposure apparatus 1 including the electron beam exposure method according to the embodiment of the present invention will be described.

  The electron beam exposure is performed while rotating the substrate 4 by driving the rotary stage 14 as described above based on the data input to the interface 20 described above. At this time, the rotary stage controller 16 controls the driving of the rotary stage 14 so that the linear velocity of the exposure beam becomes constant, for example. By making the linear velocity constant, it is easy to control the distance from the pattern recognition start portion. As a result, it is possible to produce a master disk in which data transfer is more reliably suppressed.

  Here, in this embodiment, the “resolution input means” is provided in the interface 20. A detector separately used to detect the servo signal of the servo area for detecting the track position and the information of the data area for recording information on the finally produced magnetic recording medium Is input to the resolution input means.

  Then, the resolution numerical value is transmitted from the resolution input means to the “exposure position candidate determination means” also provided in the interface 20. Based on this resolution, a grid-like section as shown in FIG. 7A is performed on the substrate 4 set in the exposure apparatus. Specifically, in each track on the substrate, the distance from one exposure position candidate α to another exposure position candidate β is set to a natural number times the resolution input by the resolution input means. Thus, an exposure position candidate is determined on the substrate.

  As described above, by using the interface 20, a place where a digital pattern recognition can be performed (ie, “exposure position candidate”) using the detector having the resolution input by the resolution input means is performed using the interface 20. Determine on the substrate 4.

  Then, position data on the substrate 4 that is a candidate for the exposure position determined by being classified by the exposure position candidate determination means (interface 20) includes an electron beam generator 2 that generates an electron beam, and the electron beam. Transmission to an electron beam control system 3 that controls the electron beam generated by the generator 2, a stage mechanism 5 that supports the substrate 4 to be exposed, and a stage control system 6 that controls the drive of the stage mechanism 5. Is done. In other words, the position data regarding the exposure position candidates is transmitted to the exposure means, the movement means, the rotation means, and the rotation control means.

After position data regarding exposure position candidates is transmitted to each component, exposure corresponding to the above-described condition 1 and / or condition 2 is performed while taking this position data into consideration.
That is, while moving the substrate by the moving means, the exposure means is used to perform exposure only on a certain exposure position candidate determined by the exposure position candidate determining means, and / or a certain exposure position. The exposure is continuously performed with the candidate for the first point as the starting point and the candidate for another exposure position as the end point. In the present embodiment, the continuous exposure is performed in the circumferential direction and the radial direction because the substrate 4 has a disk shape. At this time, the above-described exposure may be performed at least in the servo section in each track on the substrate 4, from the servo section to the data section, and in the data section. Of course, the above-described exposure may be performed over the entire track, and it is preferable. This is because uniform division can be performed over the entire effective area 19 of the substrate 4. As a result, it is possible to suppress the occurrence of data transition over the entire effective area 19 of the substrate 4.

  At this time, since a positive resist is used in this embodiment, the following exposure may be performed using the electron beam deflecting means (blanking electrode 9). That is, the numerical value in the resolution is transmitted to the electron beam deflecting means via the electron beam control system. Then, the blanking electrode is turned off so that the electron beam is exposed to the resist in a place satisfying any of the above conditions. In other places, the blanking electrode 9 may be turned on so that the electron beam is not exposed to the resist.

  In addition, after exposing an electron beam with respect to a resist as mentioned above, the master which has the data part 21 and the servo part 22 which consist of unevenness | corrugation can be manufactured using a well-known means. In short, after the exposure to the resist, development is performed to obtain a resist pattern having a predetermined pattern shape. Using this resist pattern as a mask, the conductive layer under the resist or the substrate 4 is directly etched. When a conductive layer is provided, a predetermined pattern is finally formed on this conductive layer, and finally the pattern is transferred to the substrate 4. Then, the resist pattern (in addition to the conductive layer) is removed to obtain a master having the data portion 21 having the data pattern 21 'and the servo portion 22 having the servo pattern 22'.

<5. Advantages of the embodiment>
In this embodiment, the distance from one exposure position candidate to another exposure position candidate in each track on the substrate that is the basis of the master disk is the natural number of the resolution of the inspection apparatus or magnetic recording apparatus to be used later. Set to double. Then, in order to suppress the occurrence of data transition, exposure is performed only on the exposure position candidates determined in this way, and / or one exposure position candidate is a start point and another exposure position candidate is an end point. Continuous exposure is performed.
That is, in this embodiment, the exposure position candidates are already determined by dividing the substrate from the master production stage. Then, exposure is performed based on the idea that there is a candidate for the exposure position, and pattern formation is performed.

Thereby, the occurrence of errors due to the resolution of the apparatus can be suppressed during position detection by the inspection apparatus or the magnetic recording apparatus. Furthermore, the occurrence of data transfer can be suppressed without increasing the master clock of the inspection device or magnetic recording device used for the magnetic recording medium. In addition, the occurrence of data transition can be suppressed without reducing the relative linear velocity.
As a result, the yield of the magnetic recording medium as a product can be improved, and it is not necessary to spend unnecessary time and labor due to errors caused by resolution.

<6. Modification>
The technical scope of the present invention is not limited to the above-described embodiment, and various modifications and improvements are added within the scope of deriving specific effects obtained by the constituent elements of the invention and combinations thereof. Including.

First, the shape of the substrate 4 is not limited to a circular substrate, and may be, for example, a rectangular substrate, a polygonal substrate, or a semicircular substrate.
Also, the track is not concentric but may be a straight track or a curved track other than the concentric circle.

  In the present embodiment, a magnetic recording medium having a plurality of tracks has been described. On the other hand, the idea of the present invention is naturally applicable to the case of one track. The “each track” in this embodiment includes the case of one track.

Next, with respect to the data pattern 21 ', in the present embodiment, the case where each concave / convex pattern of the master or working mold corresponds to the data pattern in the data area as it is has been described. On the other hand, as a modified example of the present embodiment, there is a case in which each concavo-convex pattern does not become a data pattern but becomes a data pattern for the first time by a plurality of concavo-convex patterns (that is, a pattern that is the basis of the data pattern). .
Specifically, when forming a bit-like pattern, the master or working mold may be formed so that four bits form a data pattern. That is, in this case, one bit may be a prime pattern, and a data pattern may be formed by four bits.

  In the present embodiment, a pattern formed by circular bits has been described. However, as shown by reference numeral A in FIG. 8, a pattern may be formed by rectangular bits.

  Furthermore, in the present embodiment, the pattern formed by the bits has been described. However, the patterns in the data portion 21 and the servo portion 22 are patterns other than the bits (for example, line and space). B) may also be used.

  Further, the data portion 21 and the servo portion 22 may be formed by mixing a bit-shaped pattern (reference numeral C in FIG. 8) and a linear pattern (reference numeral B in FIG. 8). In particular, in the servo unit 22, the entire servo unit 22 may be formed by a linear pattern, or only a part of the servo unit 22 (for example, only the preamble part 221 or other parts) may be formed as a bit pattern. good. Of course, a bit-shaped pattern and a linear pattern may be mixed in the preamble portion 221.

  The linear patterns mentioned here may be continuously formed so as to straddle between the tracks, as indicated by reference signs D to G in FIG. At this time, as shown in the above-described condition 2, exposure may be performed continuously with a candidate for a certain exposure position as a starting point and a candidate for another exposure position as an end point. Exposure may be continuously performed in a direction perpendicular to the direction from the servo portion 22 of the track toward the data portion 21 (reference D). Further, the exposure may be continuously performed in a direction inclined from the perpendicular direction (reference E). Moreover, you may perform exposure combining these characteristics (code | symbol F).

Even if the linear pattern is formed in this way, when the pattern is recognized by the detector according to the shape of the track, the pattern can be recognized at least at the start point and the end point without data transition.
Preferably, as shown by reference numeral G in FIG. 8, when the pattern is continuously formed so as to straddle between the tracks, the portion where the pattern recognition is desired in each track between the start point and the end point is also the exposure position. Exposure is performed so as to be positioned as a candidate.

  Further, in the present embodiment, when the exposure position candidates are determined on the substrate 4, classification corresponding to the track direction and the radial direction is performed. In this division, a point where a track direction line and a radial direction line intersect with each other is determined as a candidate for an exposure position on the substrate 4. On the other hand, as shown in FIG. 7B, segmentation may be performed in accordance with the shape of the track (for example, in the XY direction). Also, as to the way of segmentation, instead of using the intersection as a candidate for the exposure position, a line surrounding the candidate for the exposure position may be used as shown in FIG. 7C. Furthermore, a line in the track direction and a line that is not parallel to the line may be crossed, and the intersection or the enclosed area, or the center in the area may be used as the exposure position candidate.

  In addition, although it is a pattern arrangement | positioning in case the pattern of the data part 21 or the servo part 22 is made into a linear form, the arrangement | positioning which does not generate | occur | produce data transition, ie, the distance between the adjacent ends of the linear pattern which exists independently, is. The arrangement is preferably a natural number times the resolution.

However, when a pattern is formed by etching, the linear pattern may become larger than expected due to overetching or the like, or the position may change.
On the other hand, even in this case, the idea of the present invention can be applied even if the arrangement is changed to such an extent that no data transfer occurs.

  For example, in FIG. 1, in a situation where the detector starts pattern detection at a point where the resolution is 2 nm and x = 0 nm, a linear pattern should be produced up to a position of x = 2 nm to 6 nm. Consider a case where a linear pattern up to a position of 4.1 nm is formed. In this case, since there is a pattern at a point of x = 2 nm and 4 nm, which is a natural number multiple of the resolution, and no pattern is present at a point of x = 0 nm and 6 nm, data transfer is suppressed. As a result, even in this case, the idea of the present invention can be applied.

  The same applies to the approximate center of the bit described in this embodiment. That is, in a situation where the detector starts pattern detection from a point where the bit diameter is 4 nm, the resolution is 2 nm, and x = 0 nm, the bit center must be placed at the point where x = 6 nm. Even if the center is arranged at a point within the range of 5.5 nm <x <6.5 nm, the risk of data falling can be suppressed to some extent. Therefore, the “substantially center of the bit” in the present embodiment refers to “a portion in the bit close to the bit center to the extent that the bit is recognized at a point that should be originally recognized by the detector”.

  Next, according to the present embodiment, in the circumferential direction within each concentric track, in the servo unit 22, the preamble unit 221, the address unit 222, and the burst unit 223 are configured in this arrangement order. . On the other hand, the servo unit 22 may not be arranged in this order as long as it can be normally detected by the detector.

  Of these portions, at least the synchronization signal generation unit 221a and the synchronization signal detection unit 221b of the preamble unit 221 may be sufficient. This is because, in this embodiment, thanks to the synchronization signal generator 221a, patterns can be formed with an interval that is a natural number multiple of the resolution. This is also because the timing matching for starting the detection of the data pattern 21 'can be performed thanks to the synchronization signal detection unit 221b.

  Furthermore, in this embodiment, the synchronization signal generation unit 221a and the synchronization signal detection unit 221b are grouped to provide the preamble unit 221, but the preamble unit 221 may be formed by separating them. That is, in the circumferential direction in each track, the order of the synchronization signal generation unit 221a → the address unit 222 → the burst unit 223 → the synchronization signal detection unit 221b → the data pattern 21 ′ may be used.

  Further, as described in the present embodiment, the address unit 222 and the burst unit 223 may of course be provided between the synchronization signal detection unit 221b and the data unit 21, and the timing adjustment for starting the detection of the data pattern 21 ′ is possible. The burst unit 223 may also serve as a part for performing the above.

  After all, if the distance from the timing adjustment portion for starting detection of the data pattern 21 ′ to the pattern in the data portion 21 is a natural number multiple of the resolution of the detector used thereafter, the data portion 21 and The servo unit 22 may have any arrangement relationship.

Further, the distance between the exposure position candidates may be set as described above in each track as in the present embodiment, but at least in the servo unit 22 and the servo unit 22 in each track on the substrate 4. To the data portion 21 and within the data portion 21 may be any natural number times the resolution. That is, the distance between the exposure position candidates does not have to be set as described above between the data portion 21 and the servo portion 22.

  As described above, the servo section 22 is provided with a preamble section (synchronization signal generation section 221a and synchronization signal detection section 221b). Since this synchronization signal generation unit 221 generates a sampling timing, this timing is reset once before information is called. For this reason, the distance between exposure position candidates may not be set as described above between the data portion 21 and the servo portion 22 (that is, the portion before the synchronization signal generation portion 221a).

  When the pattern is formed concentrically, it may be difficult to set the distance between exposure position candidates over the entire circumference depending on the circumference and resolution values as described above. At this time, by adjusting the distance between the data part 21 and the servo part 22, the distance between the exposure position candidates in other parts can be made a natural number times the resolution.

  Next, in the present embodiment, the case where a positive resist is used has been described. However, a negative resist may be used. When a negative resist is used, a portion exposed by electron beam irradiation remains without being removed after development. That is, a bit-like resist layer is formed on the substrate serving as a master, and as a result, a cylindrical bit is formed on the substrate.

  Further, the magnetic recording medium may be produced directly from the master on which the cylindrical bit is formed in accordance with the configuration (magnetic material and non-magnetic material) of the finally produced magnetic recording medium. Further, in order to reverse the pattern once, a working mold may be produced from the master and a magnetic recording medium may be produced from the working mold.

  Next, in the present embodiment, the case where the interface 20 includes both the resolution input unit and the exposure position candidate determination unit has been described. On the other hand, these means may be provided in the exposure apparatus separately from the interface 20. Further, only one of these means may be integrated with the interface.

  Further, the position data on the substrate 4 that becomes “exposure position candidates” input to the interface 20 including the exposure position candidate determination means is transmitted to the exposure means, the moving means, the rotation means, and the rotation control means. On the other hand, if the above-mentioned two conditions are satisfied and exposure can be performed on the substrate 4, the position data may be transmitted to only some of them. For example, an exposure apparatus is conceivable in which position data is transmitted only to exposure means (especially electron beam deflection means), and constant movement is performed in the movement means, rotation means, and rotation control means. In this case, since it is only necessary to transmit the position data only to the electron beam deflecting means, the apparatus can be simplified, and the manufacturing cost can be reduced.

  In addition, in the order of exposure of the electron beam, the electron beam exposure may be performed from the inner peripheral side to the outer peripheral side of the substrate 4 in the radial direction of the substrate 4. You may go to the inner circumference side. That is, in carrying out the present invention, the order of electron beam exposure for the effective region 19 of the resist film 18 can be arbitrarily changed.

  Moreover, in the said embodiment, although the linear motion stage 15 which mounted the rotation stage 14 was mentioned as an example of a moving means, it is not restricted to this, For example, when arranging an uneven | corrugated pattern linearly etc., r- An XY stage may be used instead of the θ stage.

Further, this moving means may move the electron beam generator 2 and the electron beam control system 3. That is, the moving means for moving the irradiation position of the electron beam on one main surface of the substrate 4 in a direction parallel to the radial direction of the substrate 4 may move the substrate 4 side, or move the electron beam side. It may be a thing or both of them may be moved. Further, the electron beam may be moved by deflecting the electron beam.

  Further, the electron beam exposure apparatus and the electron beam exposure method employed in the above embodiments can be applied as a manufacturing apparatus and a manufacturing method for a substrate (disk master disk, stamper master disk, etc.) used in the DTR technology, respectively. Furthermore, the manufacturing apparatus and the manufacturing method can be extracted as one aspect of the present invention.

DESCRIPTION OF SYMBOLS 1 Electron beam exposure apparatus 2 Electron beam generation part 3 Electron beam control system 4 Substrate 5 Stage mechanism 6 Stage control system 7 Electron gun 8 Focusing lens 9 Blanking electrode 10 Aperture 11 Objective lens 12 Deflector 13 Aperture 14 Rotation stage 15 Direct Moving stage 16 Rotating stage control unit 17 Linear motion stage control unit 18 Resist film 19 Effective area 20 of resist film Interface 21 Data unit 21 ′ Data pattern 22 Servo unit 22 ′ Servo pattern 221 Preamble unit 221a Synchronization signal generation unit 221b Synchronization signal detection Part 222 address part 223 burst part A to G exposure shape α, β exposure position candidate

Claims (15)

In an electron beam exposure apparatus for producing a master used for producing a magnetic recording medium having a plurality of tracks or a working mold used for producing the same by imprinting,
Moving means for moving the irradiation position of the electron beam on the main surface of the substrate relative to the substrate while holding the substrate on which the photosensitive film is formed on one main surface;
By irradiating the data portion and servo portion set on the substrate with an electron beam, exposure of a shape corresponding to a data pattern serving as a basis of a data region for recording information on a magnetic recording medium is performed. The servo section on the substrate is exposed to the data section on the substrate and exposed in a shape corresponding to the servo pattern serving as the basis of the servo area for specifying the track position and / or pattern position of the data area on the magnetic recording medium. Exposure means to perform,
On the magnetic recording medium, resolution input means for inputting resolution of a detector separately used for detecting information in the data area and servo signals in the servo area;
The resolution input means inputs the distance from one exposure position candidate to another exposure position candidate in at least the servo section, the servo section to the data section, and the data section in each track on the substrate. Exposure position candidate determination means for determining exposure position candidates on the substrate by setting the natural number times the resolution that has been performed,
With
While moving the substrate by the moving means, the exposure means is used to perform exposure only on a certain exposure position candidate determined by the exposure position candidate determining means, and / or a certain exposure position candidate An electron beam exposure apparatus characterized in that exposure is continuously performed with a starting point as a starting point and a candidate for another exposure position as an end point.
However, the data pattern includes a pattern serving as a basis of the data pattern in addition to the data pattern itself. When the magnetic recording medium has a plurality of concentric tracks,
Track pitch input means for inputting the distance between the tracks;
A rotating means for rotating the substrate while holding the substrate on which the photosensitive film is formed on one main surface;
Rotation control means for controlling the drive of the rotation means;
Further comprising
In each track, at least the data pattern form of the data portion is separated in the radial direction and the circumferential direction for each bit,
By transmitting the distance (TP) between the tracks from the track pitch input means to the exposure position candidate determination means, a shift in the bit period (ΔBP) associated with the increase in the track diameter is obtained. The exposure position candidate determination means sets exposure position candidates so that ΔBP between the track (T ₀ ) and the track (T ₁ ) adjacent to the track in the outer circumferential direction is a natural number multiple of the resolution. The electron beam exposure apparatus according to claim 1, wherein the electron beam exposure apparatus is determined.
However, ΔBP = BP ₀ * TP / r
r: radius of track T ₀ BP ₀ : bit period of track T ₀   3. The electron beam exposure apparatus according to claim 1, wherein the exposure by the exposure means is performed with a bit having a circular shape in plan view. The exposure position candidate determination means is a natural number multiple of the resolution input by the resolution input means for the distance from one exposure position candidate to another exposure position candidate in the entire track on the substrate. 4. The electron beam exposure apparatus according to claim 1, wherein a candidate for an exposure position is determined on the substrate by setting to.   5. The electron beam exposure apparatus according to claim 1, wherein the electron beam irradiation by the exposure unit is performed at a constant linear velocity by the moving unit. An electron beam polarizing means for polarizing the electron beam emitted from the exposure means;
6. The electron according to claim 1, wherein the electron beam polarization means performs exposure with an electron beam at an exposure position determined by the exposure position candidate determination means. Beam exposure device. In an electron beam exposure method for manufacturing a master used for manufacturing a magnetic recording medium having a plurality of tracks or a working mold used for manufacturing the same by imprinting,
A moving step of moving the irradiation position of the electron beam on the main surface of the substrate relative to the substrate while holding the substrate on which the photosensitive film is formed on one main surface;
By irradiating the data portion and servo portion set on the substrate with an electron beam, exposure of a shape corresponding to a data pattern serving as a basis of a data region for recording information on a magnetic recording medium is performed. The servo section on the substrate is exposed to the data section on the substrate and exposed in a shape corresponding to the servo pattern serving as the basis of the servo area for specifying the track position and / or pattern position of the data area on the magnetic recording medium. An exposure process to be performed,
On the magnetic recording medium, a resolution input step of inputting a resolution of a detector separately used for detecting information in the data area and a servo signal in the servo area;
The distance from one exposure position candidate to another exposure position candidate is input by the resolution input step in at least the servo section, the servo section to the data section, and the data section in each track on the substrate. Exposure position candidate determination step for determining exposure position candidates on the substrate by setting the natural number times the resolution that has been performed,
Have
While moving the substrate in the moving step, in the exposure step, exposure is performed only to a certain exposure position candidate determined in the exposure position candidate determination step, and / or a certain exposure position candidate is a starting point. And an electron beam exposure method characterized in that the exposure is continuously performed with another exposure position candidate as an end point.
However, the data pattern includes a pattern serving as a basis of the data pattern in addition to the data pattern itself. In a master used when imprinting a magnetic recording medium having a data portion and a servo portion formed on a substrate and having a plurality of tracks or a working mold used for producing the magnetic recording medium,
The data portion is a portion where a data pattern serving as a base of a data area for recording information on a magnetic recording medium is formed,
The servo part is a part in which a servo pattern serving as a basis of a servo area for specifying a track position and / or a pattern position of a data area in a magnetic recording medium is formed,
The distance from one pattern position candidate to another pattern position candidate is a natural number multiple of the detector resolution in at least the servo section, the servo section to the data section, and the data section in each track on the substrate. Servo pattern and only the pattern position candidates set to be and / or continuously with the set pattern position candidate as the starting point and the other set pattern position candidate as the end point. A master with a data pattern formed.
However, the data pattern includes a pattern serving as a basis of the data pattern in addition to the data pattern itself. The detector is a detector that is used during or after manufacture of the magnetic recording medium and detects a servo signal in the servo area and information in the data area of the magnetic recording medium. A plurality of tracks are formed concentrically, and in each track, at least the data pattern form of the data portion is separated in the radial direction and the circumferential direction for each bit,
The master according to claim 8, wherein ΔBP between a certain track (T ₀ ) and a track (T ₁ ) adjacent to the outer periphery from the track is a natural number multiple of the resolution.
However, ΔBP = BP ₀ * TP / r
DerutaBP: deviation of bit periods associated with the diameter of the track is enlarged r: radius BP ₀ tracks _{T 0:} bit period of the track _{T 0} TP: the distance between the tracks _{T 0} and _{T 1.}   The master according to claim 8 or 9, wherein the data pattern is formed by bits having a circular shape in a plan view.   The plurality of tracks are formed concentrically, and at least the form of the data pattern in each track is separated in the radial direction and the circumferential direction for each bit. The master described in.   The pattern position candidates are set so that the distance from one pattern position candidate to another pattern position candidate is a natural number multiple of the resolution of the detector in the entire track on the substrate. The master according to any one of claims 8 to 11, wherein   A working mold manufactured by imprinting from the master according to any one of claims 8 to 12. A master disk used when imprinting a magnetic recording medium having a plurality of tracks or a working mold used for manufacturing the magnetic recording medium, and having a data part and a servo part on a substrate. ,
The data portion is a portion where a data pattern serving as a base of a data area for recording information on a magnetic recording medium is formed,
The servo part is a part in which a servo pattern serving as a basis of a servo area for specifying a track position and / or a pattern position of a data area in a magnetic recording medium is formed,
The distance from one pattern position candidate to another pattern position candidate is a natural number of the resolution of the detector in at least the servo section, the servo section to the data section, and the data section in each track on the substrate. Servo pattern continuously only for pattern position candidates set to be doubled and / or with the set pattern position candidate as a starting point and the set another pattern position candidate as an end point And a method of manufacturing a master, wherein a data pattern is formed.
However, the data pattern includes a pattern serving as a basis of the data pattern in addition to the data pattern itself. The detector is a detector that is used during or after manufacture of the magnetic recording medium and detects a servo signal in the servo area and information in the data area of the magnetic recording medium.   A working mold manufacturing method, wherein a working mold is manufactured by imprinting from a master manufactured by the manufacturing method according to claim 14.

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